I am unable to ascertain what your exact issue is because the names you are using are different to what I am used to using, (I think
If you are using the collet type prop adapter and it is not tightening onto the motor shaft well enough there is a quick solution and that is to sand or file the cuts in the collet jaws to larger gap so that when you tighten the collet the jaws are able to move closer to each other or to put their force to the motor shaft and not the other jaws.
If you are using the aftermarket prop saver and it is not tightening centrally on the motor shaft I have used brass shims to pack the prop adapter on the shaft and then tighten the locking screws. (A drop of CA also helps).
As for the plastic adapters that come with props I fit the one which is just smaller diameter than the collet, spinner, or prop saver seat and drill or file out the centre hole to get the tight fit I require. Always check prop balance afterwards.
Where the spacer is just marginally too small to fit the adapter shaft I fit the spacer to the shaft forcefully without altering the hole size and then place the prop over the slightly enlarged spacer and tighten the collet until the prop is fully seated. It makes getting the prop a little difficult to remove later but a broken prop has no value so I just cut to broken prop into pieces and it all falls away.
Just some things I do when forced to!