The best remedy is to use a good sealer to prevent problems with colored plastic. That is why sealer was created.
I've seen some say silver paint but it was pointed out that that may cause issues if you need to mask. Using the right product reduces the potential for issues down the road.
Glad you found the issue. It is absolutely necessary to take the time to test fit the pieces of an older or any kit before painting the parts. Nothing is more frustrating that finding this type of problem late in a build.
For the rounded edges I would suggest Evergreen quarter round. It come in several sizes and I would suggest matching it to the thickness of the plastic you use for the body.
Scott is a member of the board and writes for the magazine. He might have some info you want.
http://www.modelcarsmag.com/forums/profile/3265-scott-colmer/
The best rule of thumb is buy what you like, not becuase it might be valuable. First off if they tell you something is collectible it isn't. Something is only worth what someone else is willing to pay.
We see ads for clothing that are inappropriate for the site. No t sure how those images could be filter.
Besides browsing history subjects on the site also used to providing selections for ad content.
I find it amazing that the 4 top models survived all these years. So many models were lost from time. In fact the museum had significant models recreated.
It's interesting to view the trends from the past and the techniques of the past.
Nice job on the restoration Tim. Thanks for the album of pictures from the museum. Preserving the past is important.