I would like to know the secret with diamond stones. Plenty swear by them, but I do not have the touch with the two I have tried to use. I heard that you have to put some wear on them for them to work best, but I have past that point and still struggle with the diamonds.
Kinda scary to give sharpening tips to a knife maker but the only things I can think of are 1)clean the diamond stone with brake cleaner and a stiff brush in case it is loaded with swarf 2)use very light pressure when sharpening 3)try using oil for a lube just as an experiment if you have not already.
I prefer other media over diamonds myself as well but it pretty tough to beat them for something to throw in the tackle box, tool box, or hunting pack for something to have around in case its needed. Having said that I have never used the really high end "quality" stuff like DMT or Atoma. I had a Lansky diamond kit that I gave away which worked really well and right right now all I have is a ebay Chinese knockoff of an EZ lap combo stone which works very well considering it cost 9 bucks.