Mr. Moto...
I have been scratching my head over this for some time.
I really hate to cut the adapter ring any thinner.
I could go a little thinner but not enough to make a practical difference.
Don't get me wrong, every little bit helps but I really want to keep all the strength in the adapter that I can.
Machining the inner clutch cover down is also not a good idea because I'm already as thin as I can go without cutting onto the governor area.
However... I came up with another solution this morning
I will take another look this morning and see if it will work.. But I think it will.