The only problem with clipping a reflector housing to a towel bar is that if the printing frame is not directly below the light output it will not be evenly lit and the light fall off could be a problem in achieving a good print. (The effects of light intensity are a function of distance.)

I use as much as 300 watts of light and as little as 150 depending on the negative. Sometimes on really dense negatives 300 watts is required to achieve manageable times. Other times 150 watts is needed to allow adequate dodge times. I don't use a reflector housing...I use a reflector flood lamp.

Michael Smith uses a 300 watt reflector flood on his prints. I would imagine that with 4X5 Azo paper that you wont be doing a lot of fine burning or dodging.