Bit of a 'duh' moment here ... you rules junkies should brace yourselves...
If the tube thrower is right-handed and prefers to launch the tubes discus-style OVER the wall -- then put him/her on the LEFT side of the field. This way the tube will never be in question of going around the side of the wall or hitting the corner. (Just watch out if you're the driver next to the discus
).