I just ordered a bunch of case back and crown gaskets for the same reason...it seems a lot of the Raffles cases I get have damaged gaskets from the case back being installed (probably by me) improperly...the damn thing just wants to get pinched between the case and back, lol.
And water resistance tests...I'm at the point where I remove the movement/dial/hands before I test the case. If the gaskets are really bad, sometimes you get water inside no matter how carefully you perform the test.
And since someone's sure to ask, this is what I got (pretty sure they're cheaper on Ebay/AliX, but was buying something from Amazon already, so added them in).