If I was them I would just produce 3 sizes like revo 11.8 12.4 or 12.5 and 12.9 and I would make sure that I am really close to the specs, also for the end they are saying 21.5 and it is 21.0mm
And I would make it 29 inches like most shafts and not 30 inches which makes my cue 59 and not 58 and...