I've got a shoot coming up where I'll need to use several 48" flo's for a long, close-up dolly shot. Using 3 or 4 48" fixtures in a line looks like a great way to light the key area.

I've done some testing with electronic ballast shop lights with dual 48's; however, there will be a lot of other lighting in the scene, and I'd like the choice of using one or two tubes (I've been testing a T-12 fixture).

My question is (and man, I've googled like crazy): any harm to the ballast or fixture by running it with only one lamp?

And, if I install a switch to shut off the current to one tube (between the ballast and the tube) would that damage the ballast? (I'm assuming I could just stick a SPST switch on the hot lead from the ballast?)

I really need to stick with the home-depot style, 2-tube 48" fixtures - there's just not a need to invest in something pricey for one shot. I could scrim or ND the lights, but that would be about 52" x 8" of screen or gel, rather not go that route.