I like the idea of using the release into the tight arch (over the top) as a timing point for the twist, and letting the posture of the twisting position replace the tight arch position.
Actually yes, there is a great series of drills (forget the coach who put this out there) with a very specific breakdown for the front layout. It's fantastic. The kids start on track/tramp with a hollow front salto (stretched but hollow all the way through). When they can do that, they add the head and chest release as the body lines up at vertical. When that's proficient (still on track/tramp) the vertical release point is the twist.
Another from Enrique Trabinino (think this goes to him) is to use the handstand trainer for bars and set two blocks close to the height of it with space in between (think like P bars blocks). Then a cheese or something in front. they have one arm extended on each block with head/neck in between, shoulders should be on or they'd fall. They use the bungee to bounce up to a "handstand" and fall over on the cheese (they have to kind of kick at first to get going). When they do that proficiently, as they fall they can roll with arms in the twist position. That's not really exact in terms of when you want to twist, but it's a good way to encourage a later twist and some awareness of positions.
Personally I have had the best luck with front pike open bounce (arms up), then twist with the opening (half then full). This usually translates well to layouts for most kids. The kids who cannot coordinate the correct opening and then half twist out of the front pike are not ready. They need to work on orientation drills (back drop, half twist to stand on tramp). I have even seen a great coach who is a biomechanics expert use a front headspring onto a cheese wedge (pike going in, and then open), then had the kid open and do a half to their stomach help them understand and correct a vestibular problem. You have to think about how you can prevent the kid from doing the wrong thing, so this was a great idea because the kid was forced to turn upside before twisting. Obviously this drill must be heavily supervised.
As they get more proficient with layout twisting, they can twist earlier to accommodate 1.5/double technique. Usually it's better to start later, then go back and add the twist with the vertical release point.
