Gasket/insulator for Convoy C8 host

Some of the Convoy C8 hosts (Simon’s in particular) come with the longer reflector with the larger (9mm?) hole in the bottom, and a large but thin gasket for an XM-L2.

Does anyone know where I can find this larger gasket, but for an XP-G2 LED? I can get a nice beam with the longer reflector (not to mention it fits much better than the ones on FT), but centering a small LED is a biatch. And, gluing the larger gasket to the MCPCB causes artifacts.

XM to XP-G2 Adapter / Spacer