I assume it's for handlebar clearance? Maybe try the later model fork caps. They are lower profile.
Theres many reasons why I wouldn't do it, but honestly lots of bikes came with no stop ring.
You could use the thin spacer on top of the ring to act as a stop ring extension?
You will be upsetting the fine balance of front to rear height, and rake, and steering angle, but it's +/- 1/2"? Probably not an issue if you're not in Moto GP.