Ok I figured most of it out...
Now the only problem is that when I tighten the screw in the stopper ball it goes right threw the sleeve/spacer. That puts the set screw right against the trim line, which does not seem good.
How do I tighten the set screw without going threw the sleeve?
Do you have pics?
Could you slide a small piece of plastic under it? I think what happens might be that initially the screw does not go through the plastic of the stopper, but that it might have penetrated now?