I was thinking of doing something similar.

So how do you keep it from twirling around?

Some of these have a little spot for a tab to fit into. Might have to get creative on this one. I've even used super glue, behind the locking nut to keep on from spinning.... Not that I recommend it!

Hi
Disassembling the Lock Cylinder is difficult. There is a steel pin driven into a blind hole that retains it.
The pin can be extracted with difficulty, after which it could be replaced either with a new pin or the hole tapped for a setscrew.

Yeah, I looked at the schematic. I'm trying to decide if I want to go that route.