My 52 A10 leaks from the primary cover joint after chagning my clutch plates. Where in the US can I get a thick gasket, both of the ones I ordered were thin paper. Anyone ever cut one out of cork sheet?
Not an answer to your questions.....but have you considered making your own out of gasket paper? I use a 1mm thick "flexoid" brand paper, some use old cereal boxes etc
it takes a while to make one but it stops you being reliant on suppliers, and you can make pretty much all your own gaskets once you have the punches, and a paper source.
I make the primary gasket deliberately oversize so that it sticks out inside and outside the case a bit, this is not an issue with the primary drive (might be with an engine gasket) and seems to make it less likely to leak, and it certainly makes it easier to make and fit, as a bit of misalignment does not matter, and it's less likely to rip etc.
You can't easily trace around the inside of the case (e.g around bolt holes) so I just do the cutting of the inside about 5/8" (from memory) from the outside trace. It might need trimming a bit to avoid hitting the chainwheel.
I stick the gasket to the inner then use a couple of long 1/4" whitworth bolts with the heads cut off, temporarily screwed into the inner case, to help guide the case on, thus avoiding disturbing the gasket goo you carefully applied. I only goo up the bottom edges.
If I can be bothered I trim off the excess gasket showing on the outside, using a blade.
The "wadd" punches I use were dirt cheap and one of my most used tools now!
I spend more time trying to prevent leaks from the case bolts, rather than the case joint