So - I got a 2" Fernco, which was the right size - about 2.75" outside diameter.
Got the name ring off and started on the lens assembly. Tried all of your tricks, and nothin' doing - except I did manage to remove the lock ring for the front lens element! (Guess I can clean out any dust inside, right?)
The main lock ring was TIGHT. I realized I needed a lens spanner wrench. Never have owned one of those. Even when shooting 4x5 product, I never had a problem with lens board lock rings.
But - am I not a man? A man surrounded by tools and whiskey, fine tobaccos, aged cognacs, asian supermodels and... grip gear. Lots of grip gear. From the fine folks at Matthews and Avenger and Filmtools.com.
Gentlemen, may I present the ghetto-span-5000. The lens assembly is out! What's next?