Cam degreeing help me understand!

You need .903. 7/8 is .875. lol

Yes 3/4" dowel is .750 ths for the sake of conversation.

My rough draft dowels that I had on the shelf are .870 ths, which is still too loose in the .904 ths lifter size hole. My stock lifters measure .904 ths that is the size I would make the new dowel starting with 1" stock (.100 ths)