Sounds like a good plan. Congrats on your new airplane!
One question, have you had the pipe off yet? Besides the alignment it can fit too tight, too loose, anywhere in between. Mine are slightly tight, I have to fight to get the gasket in.
So.... High EGT can be caused by an excessively rich mixture. Fuel is still being burned when the exhaust valve is open. This scenario might also show lower CHT. But I am at a loss to explain why it would only be happening in one cylinder, and why it would just start randomly. Is the exhaust valve ...