Laughed out loud at the part about the lens unscrewing from the mount before the ring would turn. That is wild! I have never heard of using a sink stopper on a lens but it makes total sense. The bigger surface area gives you way more grip and spreads the force out so you are not twisting the barrel. Now I want to dig through my junk drawer and see if I have one of those flat stoppers to try on an old Vivitar I have been fighting with.

Wait, so you made a bag out of old jeans and now you're worried it's not working because of some ice water? Can't you just line it with a trash bag or something? Seems like you're overcomplicating a 3 dollar project.

That "back the setting off to zero" thing reminds me of my grandpa always leaving his truck in gear with the e-brake on.