ok here's what ive learned this weekend, the Gen gasket is slightly taller but still fits in the groove, however it is about 0.15mm thicker not much, but too much to get the crystal in,
Mounted my Dremel in a vice with a stone grindiing tip on and rolled the gasket around it to shave it down a bit, and managed to press the crystal in, although it was real tight it failed a pressure test, i guess there is no way to shave it down evenly all the way round,
so a big waste of time and back to the rep gasket and a not very tight crystal