2 lights in a 4×4. The canopy was not level. Just let them grow wild. Was mostly doing as a trial just to see what would happen. As it turns out, one plant liked the extra light and grew so fast and tall that it was within 6" of the light above it when raised as high as possible. Ended up moving 3 plants to a 5×5 with 3 550s on movers just to concentrate on the crazy mutant that loved the light.
The 3 that moved to the 5×5 became extremely stressed after the move. My fault as continued hammering them with lights at full strength and too close. Really wanted to see what happens. Now I know.
The big one shows no leaf damage just some bleaching. She did foxtail some though. At most vigorous growth during the stretch she literally grew 2" up every 24 hrs.