MADIMOD- What kind of reflectors are you using? Mine fit without any problems.
Toasty- You really shouldn't have a problem fitting all IC reflectors (great choice btw). You should double check for sure. Each one is 2.5" wide. As for comparing the two ballasts, I don't really know the answer. I had a couple WH5 lying around so I went with those. One of the things I really like about the WH5 is that they each can run 2,3, or 4 24w bulbs.