2-3 ft your gonna be just fine. Them ice boxes seem pretty slick. I'll let ya know how well they work. My buddy has- 2 for 2k hes gonna be setting them up in a few weeks. Along with the mini gen co2.
them ice boxes will do the job if you have the right chiller.right after i finish i'm doing my setup like that one per each light.2-3 from tops is fine if temps are 75f but 83 will cause some little problems.your friends setup is going to be nice