FabVape in Greece has 23 mm matte AD rings in stock right now. The places I try to stick to are the placed in Germany. I ordered the Glass-
tank and a few other things from inTaste.de Monday of this week, they got here Friday via FedEx. When it comes to the hard to find items the GG store in Spain has most items but you're looking at a 2 week+ wait on shipping (and they don't give you a choice on shipping) inTaste in Germany had a shipping cost of ~10,00 Euros, while it's always a flat 15,00 Euro fee shipping from Spain. I'm still waiting to see how fast FabVape can get an order here.
Imeo if you're reading please stock inTaste with plenty of product for those of us U.S.A GG lovers.
Good Luck with your search!