Raydawg,
I don't know what it is about that area, but the same red RTV that I would use on a GE T701C/D or on my APU is NOT good enough for that joint. I tried it; it turned orangish-pink, dried up, and flaked off in about a week.
I never did try the grey stuff we put on the thermocouple, but I'm not so sure it's that different... Just shim it right the first time, and if that don't work just weld it on there.