GeoDisc and related products does not have a Pivot to Spindle Ruler, so i have NO IDEA how do you guys are using such products if you're gonna swap a tonearm ??? Maybe it's good for ONE fixed tonearm on a turntable, but devices like GeoDisc are useless if you have many tonearms. Precision pivot to spindle setting is the first step for any toneam setup. This is the reason why Dr.Feickert is always better.