x3 on the cork seal even on pans made for the rubber. i had a leak that i thought was a rear main, turned out to be the early poor design 3 prong rubber seal that was leaking, re did the pan gasket using a standard felro gasket but used the cork gasket as MR P body explains here, been pretty much leak free for 7+ years now. the later 5 prong rubber U seal is better than teh eralier one but the cork is much better when installed properly.
https://pontiacstreetperformance.com/psp/Sealit.html