Blackfoot: I would suggest using the RTV and no gasket material. It was designed this way and works well if used correctly. As AFJ said keeping both surface areas clean and dry are critical.
I personally would use the sealant available from your local GM dealer, it works much better than any other that I've seen. Hey, if it can keep a Chevy from leaking, it's got to be magic..
p.s......still need the 951 clutch lever...