I have one of the Integy units and it's a nice piece. I don't know how accurate it is on the higher rate springs though.... I do know that there can be a lot of inconsistancies in the spring rate from the same manufacturer within the same "color" rate due to production tolerances and such. There is a considerable amount Of science that goes into rating springs, but if you can come up with a repeatable method that works for you, you will be amazed at what you can learn. Looks like bang for the buck, it would be hard to beat the drill press and scale method. It's essentially what we do on the big cars minus a few widgets and gizmos. Haha
Chris