well i should be revising but here's a nice drill i've thought up to help your short bump snake players, and maybe even some back players if you feel like it.
basically it's a rolling snake bump drill so doesn't stop and you get to use the field more efficiently. So you have two players breakout to the first GOD bunker (the first bunker that fills the snake), and they begin snapping, the one who gains dominance must bump to the second god bunker and wrap on the first guy (if he hasnt followed him). Here you may go for a second round of snapping or go straight into the snake, but at this point the second two players are ready and go to the first two bunkers. The first two are now in the snake and snapping down the tape for dominance. If one person gets shot, you can have winner stays on or they can both leave, up to you, but the player closest to the snake must pay attention to his man in the snake, and fill as soon as he starts to walk.
The difference in the snake is, the players have to shoot low (or lie and shoot, you can have some 'X' players to make sure they cannot be shot from cross field).
The drill is much like you'd expect a game to go, only its focused on the 1on1 mirrors gunfighting and moving as soon as they gain dominance, and also snake snapshooting which you dont get as much practice at and you see alot of players doing awkwardly or exposing themselves to cross field shots.
To make it more advanced, add in back center to make the breakouts more realistic and to help stop the players bumping. And snake corners to make the snake battles more interesting.
to make it more simple, forget about the God bumps, but it helps to get you in game mode and ready for the snake gunfight.
Even better, like in Dave S ECI's drill, you can start the drill from the opposite side to the snake, and use every mirror'd bunker to bump to before the snake, meaning you use even more of the field and get more players on at the same time!
if you dont have a limit on paint you want to use as much of the field as possible, you dont want half the team standing watching two players in a one on one.