What is the manner in which those meditating on emptiness actually bring their contemplations into a practical, experienced form? In other words, how does insight (on emptiness) become effective in every day life?
Your question is a good one. If I understand it correctly you are referring to the process of "bridging" your experiences in seated meditation into the time between such meditation sessions. You recognize that there is such thing as focusing one's meditation in a certain way (on emptiness) and it's not clear how to bring that focus to one's daily activities. If that isn't your question I apologize. If that is what you are asking then it's important to understand some of the practical aspects of focusing on emptiness. Focusing on emptiness is not necessarily the same as meditating on emptiness nor is it the same as realizing emptiness.
Focusing on emptiness is using the idea of emptiness as taught by the Buddha to change the way you see your self and your life.
Focusing on emptiness can be described as keeping impermanence always in mind. In other words, whatever you see/hear/taste/smell/feel/think ALONG WITH the organs you use in order to see/hear/taste/smell/feel/think are going to die (or end) REAL SOON! That type of reflection has the PRACTICAL effect of doing two things. First, it causes an increase in awareness of the precious little time we have in this body. And second, it creates an ambivalence towards things that waste that time.
In other words, when you come into awareness of death you start to realize the futility of grabbing onto things you experience with the senses and you also realize the limitations of those organs you are using to perceive objects. This creates dispassion and eventually revulsion for these habits of grabbing onto such ephemeral, unrewarding objects. The nature of all objects of the senses is to burn unto death (as taught in the Fire Sermon [SN 35] among many other sutras). When you meditate on emptiness you are focusing on that truth within all objects of your life and all aspects of what you call your "self" (those organs of perception).
You don't actually need to "sit" for meditation to "meditate" on emptiness in the way I am describing. "Sitting" actually makes it easier to see into this component of fire/death within all objects and without sitting, perceiving objects of everyday life in this way takes even more courage, determination, persistence and most of all, faith in the dharma (+the Buddha & the Sangha). But even if you sit and experience the jnana states sequentially the meditation on emptiness must continue in the same way at each new state. Even the jnana of "nothingness" (one of the highest states experienced by the body) must be seen with using this meditation on emptiness; that is, 'this state is temporary, it too shall pass, it too is on fire.' That is why Sariputta would describe his experience of the jnanas as (forgive my paraphrasing): 'And then the first jnana assailed me, and then the second jnana assailed me . . .' etc! [I will look for the reference to this sutra and add it later, it's in the SN]. The mind as an organ of perception is on fire/subject to death/empty and so, the appropriate practical response to the experiences it delivers is the same: dispassion, revulsion & eventually release.
In your original question you said you had an insight, that even meditative states are "empty". This is a very important insight. From Pali Canon we know that Buddha came to the same realization - that any state is just that, a state. Once you really see this, once you see Emptiness, it becomes clear that nothing in life is more important than anything else. Everything is relative, has relative importance - but in the absolute sense these distinctions don't have inherent meaning. Relative is relative. This does not mean it is not real, it very much is, but it is only real within its certain context.
In Mahayana this realization is considered the first real "entry" into Mahayana proper. If you follow this realization through to all its various implications, you will see it has very far-reaching effects.
For one, you suddenly lose interest in partaking of the worldly drama. Why sweat and worry about stuff if none of this has inherent significance?
Secondarily, you may suddenly feel spontaneous compassion to "sentient beings" (people) that still take this so seriously as to try and attain some "better" states, only to keep going in circles of endless frustration.
Finally, since you are no longer attached to any particular state, you are good with pretty much any position of mind, feelings, and body. Their positions no longer bother you. You can even be frustrated or irritated, so what? Of course, the law of cause and effect is still as operational as ever, so allowing the mind to be in unwholesome states and allowing the actions to lead to unwholesome states is still fully effective at creating bad karma. But in some very deep sense, bad karma, the karma of creating suffering - is part of life. In this sense, it is okay, too. Everything's okay.
So you can feel a relief. You can also feel a little depressed, because nothing really makes sense, all games are over, nothing further to be done. Even the quest for Nirvana that animated us for quite a long time, suddenly loses its shimmer. "Samsara and Nirvana are just two poles for tying the donkeys".
Then you realize that this mindstate - either of relief or of depression, is also empty, since it depends on your perspective or position, on your interpretation.
If you really follow Emptiness through to all its implications, it hits hard. There are countless stories of people feeling like they lost all ground, all will to live on, feeling as if they have died and so on and so forth. Sometimes this is followed by regressing back to a comfortable state. Sometimes this ends with psychiatric issues. And sometimes this matures into what Mahayanists call "union of wisdom and compassion" or "union of freedom and skillful means". Meaning, the deep understanding of Emptiness gives one wisdom (of not getting stuck in one-sided perspectives) and freedom (personal subjective sense of relief, no pressure, no judgement) - but also a sense of empathy and responsibility for the fellow sentient beings.
The above is partially anecdotal and partially a generalization of my own experience. What's important to understand, realization of Emptiness does not make you a superman, nothing like that. If anything, it makes you see very clearly, that in the grand scheme of things, you don't matter at all. And that must be the most sobering spiritual realization of them all.
Welcome to Mahayana!
Insight on emptiness make you aware of the illusory nature of the self. Which means it makes you aware that all forms are empty of a self and clinging to self(ego) is meaningless and only cause you suffering. Having glimpses of emptiness can bring you temporary calm, peace and joy. But it is temporary. After experiencing Nibbana many times-which is the absolute perfect, indescribeble state which brings you perfect peace and happiness during you experience it- you will also experience different types of amazing states of mind. At one point you experience a state of emptiness-which is an amazing state too-where you don't feel a body anymore(the body dissapears) and everything turns to black. All of the boundaries dissapear and every-thing dissapears and transforms to boundless formlessness/no-thingness. You become "no-thing" and everything. But it doesn't mean "nothing" but it means you don't have a form anymore. This is also an amazing and deeply calm state but it is not equal to the perfect peace and happiness of Nibbana. After experiencing this emptiness state few days later a person would start to disidentify from the core of subconscious mind which would eventually make a person free from the identification with the self completely and would make it possible for a person to have very deep peace of mind continously.
The last realization of the emptiness that I described above is a signpost for a person that the ego is about to enter to a death process in just few days later. But only after the realization of Nibbana these things can be possible. Experiencing Nibbana many times makes it possible to enter to this "jhana"(I don't know the "number" of this jhana LOL but it is undoubtedly a jhana) that starts the process of the death of the core of the self or you can say the core of the subconscious mind.
But If you're a beginner meditator you don't need to think about all of this and you can have this understanding that having glimpses of emptiness is always possible and it brings you temporary calm and temporary understanding of the illusory nature of the self.