IIRC, you said up thread that the crank isn't fully tightened onto the spindle. Is that correct? If so you would be best off in my opinion getting a slightly longer spindle. Or, if there is a frame builder near you they might be able to crimp the chainstay for you without damaging the entire chainstay or much of the paint.

Just be sure that whomever does the work does not do it by whacking the chainstay with a hammer. I was on a long ride in Toronto Canada when i noticed my crank was almost touching the chainstay. I stopped in at a bike shop and asked them it they could move the crank a bit to the right so that the chainring wouldn't be so close t o the chainstay. As I was just passing through Toronto I asked them if they could do it that day. They said sure. I figured they'd put a spacer between the fixed cup and the frame. Nope, they hammered t he chainstay. This is the result.



Cheers