There are a few other threads currently that deal with this topic.
I have emailed Mark @ OrientUSA to see if he can give the difinitive word on the diameter and thickness of the the stock mineral crystals.
I also emailed Harold Ng at yobokies and asked the dimensions of his domed, blue AR tinted sapphire crystal that we KNOW fits the Mako (and presumably Ray). I know it fits the Mako because I had one installed on my Blue Mako.
I recently read a post that included a link to this supplier of crystals which looks like a very promising one to supply the sapphire crystals that are so often desired as an upgrade for the Mako, Ray, and Mako XL.
Krysworks Online Store
On other posts I have read the the dimension of the Mako/Ray crystal is 31mm x 3mm and the Mako XL 32mm x 3mm but I don't know if that is absolutely accurate AND if the dimensions would be different if a domed crystal was selected. If Harold provides the dimensions on his domed sapphire crystal for the Mako then we should know.