Hello Tom,

I usually buy my Autavia 11630 glasses here, good quality and cheap price:

http://www.swissforniture.it/it/vetri-minerali-temperati/2840-vetro-minerale-piatto-tondo-ht-300-mm.html?search_query=vetro&results=34

You need the 32.0 mm diameter (that is the 320 one) but could be useful to buy also the 319 and 321 ones (the latter especially if you will reuse the old gasket).

Hope this helps.

Best.

Gianluca