I did all my correct measurements before I purchased the race face stem for my scooter to delete the failing folding T-Bar handle bar. Installed the adapter with the shim and then tested it out and had considerable amount of play left and right and couldn't get a tight fight. I ended up drilling a 3/8 hole directly through the race face adapter and my stem of the scooter and put a bolt and two nuts with a locking washer in between the nuts. Painted to match of course. Now there is no play in the adapter left or right or even up or down. Thought maybe there could be a top adapter for the pole stem like a mountain bike would have included in the kits. I mean the fork stem on a mountain bike.
Great idea thought, just need more improvement on the kits with extra parts to help with stability so I can keep my teeth riding my scooter. Thx