Why does the mat have to be glued to the platter? Seems to me you’re better off with nothing between mat and platter, for best energy transfer.
@lewm It depends on the platter pad to some extent. But the pad, if its doing its job properly, is damping the platter as well as the LP.
To do that it must be the same hardness (durometer) as the LP, and then have damping properties so all the energy coming from the LP as its being played is absorbed with none reflected back.