In my opinion you can go as far as 60"x36"x20-24"H w/o any problem.
36" front to back on a 4 bulb unit?
I think that might be a bit of a stretch.
Guys,
i have 24" unit with 8 T5s,but running only 2 channels. today i decided to add 3 rd channel with 2 Blue+ bulbs but softwear only show only 2 channels.i reboot controller but still showing only 2 previous channels.. iam doing something wrong?