Many times, an engine that comes with a collet mounted prop driver (like most ST's, for example) can be adjusted with a washer behind the collet, or even by shortening the collet a bit on the back side. The later may require some rework on the back of the prop driver, or not.

I have a VF and some PA's and frankly don't know how the prop driver is secured on any of them, but I'd almost bet on use of a collet...clearly the best way, IMO.    Steve