In building a UV lightbox using F20T12 BL tubes, I was looking at two different ballasts. The first is a RL2SP20 TP, which has a ballast factor of .61 and the other is a HM2SP20 TB, which has a ballast factor of .85. With limited knowledge, it seems that the higher the ballast factors the more light output. So my question, is there much difference in printing time using one or the other, this is for platinum/palladium printing. There have been some excellent discussions about the tubes, but I couldnt find much on ballast. Any help would be appreciated.