@big_greg - Hi Greg. Do you have the Achromat that is specifically designed for the SL1200? How does it fit? Does it have a channel cut out of the bottom to fit over the ridge on the outside edge of the SL1200 platter? Or is the diameter small enough to sit inside of the ridge on the outside of the platter?
Just curious because it would seem you would want the aftermarket mat to be in contact with the whole platter. A stiff mat that did not fit either inside of the raised ridge, or have a channel to accommodate the ridge, would not sit flush against the platter, correct?
BTW, with my Audio Technica AT-VM740ML, I cannot get the VTA correct using only the stock mat. The VTA adjustment bottoms out before I can get the tonearm exactly level. It's close, but I would like to have a little adjustment on either side of level to test different VTA settings.