More importantly, your method of mounting a can onto a Pullmor chassis cleared a huge mental roadblock I had against putting one into my CV. It's great to have a plan of attack rather than experimenting.
Re: Flywheels. I left the flywheel on the small China drive motor I installed into a Lionel 18000 B6. It sticks out of the back of the cab but the silent running and ERR cruise makes the whole affair so much fun! A more than fair trade off IMHO.
First time I cut the whole back side of a Mohawk chassis off, I thought to myself, oh god what have I done!...the first cut on the chassis never gets any better!....but you can breathe a little easier once you get the motor mount on.........Pat