I have a set of Porter Cable bushings that fit very snuggly. It is Porter Cable's standard by the way. I guess it's kinda what happens when a 3rd party manufacture makes parts for someone else's standard. Should fit doesn't always match reality.
Hopefully your idea will work, and the bushing will not move around in the .030 slop. For things like dovetail jigs, .015+- will give really bad results.
Lets us know how it works out for you, please.
I have found that hand tools are the best choice when I want to make mistakes at a slower rate of speed.
I don't suffer from insanity. I enjoy every minute of it.