Did you see the ultra-tiny flywheel Mike did?
The other times I just spent forever turning the OD on a lathe. Wasted a lot of time, and threw metal swarf all over the place.
This time I clamped the flywheel in a vise, had the CNC drill 40, 1/4" holes in a circle with the holes almost touching, then ran a 1/4" end mill around to clean up the cut. Then gave the OD a final wipe on the lathe. Much less time and effort, much less mess.
Debating poking holes in the flywheel to allow me to hold it to torque the nut. Might just be lazy and use red Loctite on the threads and bias the nut with a rattle gun.
My only concern with the real light flywheel is that once I do the high compression 695 top end, engine braking might be a bit much, and the idle might not be as smooth.
One way to find out