Why not let the level threes work at the same time as the level twos instead of the level fours? This was a ridiculous decision on the part of the head coach (or whoever handles scheduling,) and they knew how old the girls were when they made it. More than just yawning in school and a lower reading score, we're talking about a safety issue if the girls are sleepy at practice. It sounds like you need to make it very clear to the coaches that unless they want to lose more gymnasts (which it doesn't sound like they can afford to) they need to make your children's well-being their top priority. Four out of six parents is more than enough to present a united front. Don't forget, you are the client and you have the power. Asking for age appropriate practice times and adequate rest is not unreasonable, and you should go in with a few ideas (full, structured Saturday practice, working with the level twos, etc.) that you can present as compromises. Be strong!