Two Lumenarcs over a 6-foot tank?

[fkshiu]

Would I be able to get away with using only 2 MHs with Lumenarc reflectors (either the big ones or the minis)?

Secondly, I do plan in using T5 supplemental lighting, but how feasible is it to squeeze them in if the tank is 24" wide given that the big Lumenarcs are already 19" wide.

I plan on putting SPS/clams right under the reflectors with LPS/softies in between and on the edges.