The reason Shaptons are so exceptional is the diamond composite and that they're so flat to begin with and that's what you're really paying for with that stone. I have used a GDLP on Shaptons as that's part of the Shapton system. When you have something that flat, a rock solid holder is necessary to keep it flat and the lapping stone should be consistent with the technology. The Shaptons start out two orders of magnitude flatter than a DMT which is +-.001" across the surface. The Shapton is .001mm which is a whole heck of a lot flatter. I've been playing with Shaptons (with Harrelson Stanley) lately as I'm going to be carrying them in a couple of weeks.