I'm pretty happy now that I'll be able to use the first one, without any balancing marks and drill to the plan satisfactorily...

I have worked out how to make a drilling jig for the job and that's the way I think I'll go.

With regard to the other flywheels, to avoid any problems, I'd probably send them to a shop with a 360 crank and have it done there. The 130-tooth flywheels especially, I feel, need proving. Now that I look at my 'stocks' I'm surprised that I have so few unaltered flywheels. Or more to the point, so many which appear to have been altered.

When I get around to making the jig I'll post progress pics etc. Thanks very much to Mike (mkdart) for the additional help he gave me.