Hey Tiny - I think the spacer would have the same angles as the built in race so that it works with the bearing - that is the theory but how to find that special spacer...
Trying to build up the fork I think it would fail over the long run...
Yes, If I am not mistaking, someone shared a link to an example of the kind of spacer you would need, but it was the seller of the frame that provided that spacer. You would indeed need a spacer at an angle.
And building up the fork is not the best solutions, but maybe if you use carbon epoxy it could work... It's what the fork is made off after all... Maybe with a very thin and small strip of carbon cloth. But this would be the solution you could try instead of scrapping the frame
It's a shame that after all this time you are still struggling with this frame...