ive actually been practicing many different meteor throws and hand positioning for said throws, what ive found for the most part with the weave toss that hand positioning affects how high it goes and how many rotations the meteor makes, the closer to the center the more rotations and the lower the apex of the throw, whereas if holding it off center you can gain extreme hiegth. As for releasing it, this can be a difficult concept to begin with but in all actuallity its rather simple and follows the same principle as spinning the meteor splayed out, by controling the small(leading) half of the meteor the rest just follows along. So with that in mind when you are preparing to throw you want to make sure that your meteor is moving in the direction you want so that at the end of its path the forward section banks upward, its in this section of the spin that your going to be throwing, so as the head comes around and begins to climb you basically snap the wrist upwards and throw up the smaller (forward) half straight up, the long half will follow along and depending on how much momentum the meteor has built up it should whip up and around continuing the weave up in the air, this throw can also be done from the rotor.
As for the second throw its pretty straightforward, one handed butterfly held in the center, as the two halves make their bottom pass push up harder and open your hand(palm up) the meteor should literally just jump out of your hand, this one is slightly harder to catch because of the lack of movement on the Y plane to keep in balanced and from moving far off to either side during the rise and fall, instead what is produced usually is a relatively straight climb, and a subtly curved descent usually back, so taking a step and a half or two back is a good idea.
Third, and most difficult of all would be the horizontal rotor(above the head) toss, beginning from the above the head meteor you create a slight bobbing in the meteor, i do this just by bending my knees down just enough before pushing myself back up to create this bobbing motion, let it bob once and then as it bobs downwards for the second time and begins to move back up, open you hand and push up hard, it should just sail into the air and come back down right ontop of you.