I would guess that using a blank LP would give you a baseline for AS force, because I am guessing that the skating force on a blank surface would be a bit less in magnitude compared to that of a stylus traveling in a groove, where the contact points are to the side walls of the groove. Whereas on a blank LP, the very tip of the stylus is all that would contact the vinyl. Plus, the stylus is not having to negotiate tiny undulations due to the recorded signal. So, maybe less skating force. If all this is so, then the blank LP could give a good baseline from which one might need to add a bit more AS force for playing LPs. I dunno. I certainly never meant to say it is dead wrong to use a blank LP, but I prefer either Mijo's suggested method (using the run-out grooves) or my own, which is apparently also the approach recommended by Frank Schroeder. (At least I am in good company.) I think this is enough tortuosity for all of us.