Good feedback guys!
Thanks for sharing your experience.
I have used all the tips and a butane torch to boot, and have finally WON the battle.
Turns out you do have to get a touch rough with these units to 'wrench' them apart.
In fairness to ST, these ones are 10-ish years old and pretty thoroughly seized.
Rust and gum both...in spite of gobs of after run oil!
I'm looking forward to new bearings, seals, rings, and a couple of good running 90's, I hope!

It's all fun!