According to Daniel at luminarc the mini is ideal for 2x2 coverage, so 2 would be perfect for a 120 (or at least they better be as mine are in the mail ).
The link I posted earlier is for the mfg, I don't know if you can find a discounted price elsewhere?
Hey John let me know how you like them when you get them in. I am still debating moguls or hqi. I want to try out the de phoenix 14k's. Did you order the ones with the black casing? or just the reflector? Im guessing that just buying reflectors would be best since most would run some kind of actinic and to do a nice retro, need a damn canopy.