I'm thinking of updating these charts again.
1) Which of these is the most useful to YOU? (I'd leave the measurements alone on the "IMPACT" one.
2) It sounds like my "extreme" version should have a larger cutting area for 7" records
3) It seems to me that the "total rotations" columns aren't really necessary. Does ANYONE use those? I sure don't. They are interesting to look at once, but they don't help you cut.
4) I think it might be useful to include a columns featuring the RIAA standards for location of inner locked grooves. I WOULD use those.
5) It would be helpful to include data on the absolute distance between grooves at a given LPI. Maybe I'd call this "Absolute mils." or "Groove Spacing" ... looking at boogievan's thread here: viewtopic.php?f=9&t=3863&p=26013#p26013