Gotcha... It's coming up. I just did the "2 collar" test and with an 8" rod (about 1" diameter) and it came up with a delta of 0.0003"; repeated 3 times so it wasn't luck. I'm sure I could tweak it more but don't find it necessary. That method seems to be the real test as it's done w/o a TS center. I have a good piece of 2" shaft but can't hack it up right now because I think it's needed next week. Anyhow, the longer, 2 donut method is done with a TS center. At the moment, I need to run down to a buddys house because he borrowed my my "balanced lathe dog".
Ray, I'm looking forward to this. Please, if you find the time, do this.