Well at least now you know. I had to pull my ps pulley forward a full 1/8” to get it aligned with the water pump and crank pulleys.So the alternator to wp and crank pulley is very accurate. (Tops the pulley is out a 64th over the roughly 4" pulley) like you said it is almost impossible to measure the ps pulley and the AC... But they are very close. Wouldnt imagine them making that much strum on a belt that was in a different vgroove though even if they were out.