I read an article a while ago, where a guy put Ferrari Modena wheels on a fox-body.
The wheels were, as you said, just a tad too big wheel circle wise.
The guy, who was a previous employee of Ford and Saleen, just hogged out the holes to allow for a larger wheel circle.
I don't know if this is a safe way to do things, but I guess that is one option to go with.
If you are buying some new Weld wheels, why not buy some that will for sure fit?