Sorry to be a party popper, but they are all on one reflector, and hence it's going to want modification for anything high-light that should be OK under 4 T5's as they won't perform well without individual reflectors. You'd have been better off with a second hand Arcadia unit. They come up in immaculate condition with individual reflectors in that size for that price regularly, rather than buying something that will require work...
All the best
Rabbut