I think you'll be really happy to have that Frank. I made one in the long ago, though I don't quite remember where I got the idea for it. Might have been from Dean Williams, back when he was an active member of the other Forum. His website probably has a build thread on it, or at least a recommendation for it. In any case, it will get you close to good positioning far faster than manual indexing with a gauge will, though for ultimate precision, you should probably do a final finish on any set-up by checking with an indicator, just to be sure.