Skipping the mirror foam check is just asking for trouble. That sticky mess is the first thing I look for on any old camera. The extra cleaning time is a direct result of not doing the basic prep work. I use a simple mix of isopropyl alcohol and a lot of patience for the shutter blades. It's slow, but safer than hunting for a stronger solvent after the fact. Starting with the main mechanism before checking the foam is putting the cart before the horse.

Ugh, that's brutal. Sounds like the coating can't handle the actual thermal stress, so it fails exactly when you need it most. I'd stick with your old method, it's proven.

But how bad could it really be?