Actually, in the TOMG transcripts, Michael very much keeps urging the group to meditate and even makes claims such as if 60% of the world population would meditate, there would be no wars, we would have answers to interstellar travel and stopped wasting our time on crap (my words - they said it differently and basically meant various ways of hostility, separation and maya) and more. I don't know how much of that is really Michael or why this has not made it into MFM or why later channels don't get this through that much, but I think it has to do with tailoring it to the audience and with what do people ask about. If people asked more of the questions you have just asked or even requested a more thematic and systematic sessions about this, I am pretty sure Michael would deliver.
As to what sort of meditation to choose or practice - I think whatever suits you really and that they all accomplish some sort of Essence contact. For some people sitting in a lotus position would work (I am not one of those, lol), for others, swimming would do the trick better. For others, lying position is best. Sometimes guided meditation is good, sometimes just some music, other times drumming, really it depends and does not matter in my opinion.