Flouro's are prettty good/effecient for their price, i have to move my cacti inside for the winter here pretty soon, and rather than winterize them,  i think i'll put them under 2x50w t5's, one 6000k and one 3500k, with a small (35-70w) ceramic metal halide hid light to give it some full spectrum light, uv, and all those other nice spectra our columar friends like.

Should prevent them from getting spindily, (reaching for the light) with the t5's, and i can get those close. Then the cmh, or cmh low wattage (sub 50w bulbs) should kick off enough heat, and extra spectra as well.

Since they're not 400w bulbs, i'd imagine you could get them much closer to the cacti, and get some heating action going on at the same time.