David retro
Site Supporter
We now have the tapered ones in stock

You urgently need an protector on that hole...
Oh I see, that makes sense.So the cone rubber goes on the bottom with the wide side up, you can then cut a piece of the existing sleeve to use as the spacer. Normally the spacer would be nylon (and therefore wouldn't compress) so you can't fully tighten the screw. Should work fine though as per @David_Vi suggestion.
Pic with dimensions: https://www.ipdb.org/showpic.pl?id=588&picno=8534
This was what I did when I replaced the plastic 12 years ago, it helps protect the plastic from getting hit by the ball. I've now replaced it with the snackbar mod but it was still on one piece when removed.Your problem may be that the plastic is not bending enough over the scoop. You need to heat up the plastic (I used a hot air paint stripper on low setting) and bend the plastic upwards so it fits over the scoop.