WC is an acronym here for a toilet system just kidding friend.I think it's ok to just use any old hardware o ring kit it does'nt get that hot on the intake side even after you shut the engine down,that's been my experience.A lot of chat was happening about plastic backplates so go figure (means have a bloody good think about it in australian) i have two 82's with lots of flying time,plastic backplates and so far no problems,they support the intake tube well.Dave if you can remember the 91 figures on a 14x6 it would be interesting to compare them to the 82 you used to have.Like you mine are very close within 500 odd rpm and the newer 82 is lighter and powers 46 size deccys well.
Barry maybe someone here will figure it out.I'd cheat since i'm development friendly and bore a whole right thru the middle.