Do you use a loupe/microscope to look at the edge? I picked one up for like $12 at radio shack and just check the bevel to make sure the scratch patterns from each preceding stone/grit level are completely removed and the bevel is equal. The differing scratch patterns are fairly easy to see and differentiate with that particular microscope - I think it is a 60-100x power. Just what I do to check the bevel and make sure it's time to move to next stone... Works very well for me.
Cheers,
JC