I think I'll try putting a strip of electrical tape vertically on the frontstrap as a test. Electrical tape has a tendency to slide around with friction so I'd rather put 2-3 pieces horizontally and trap the ends under the grips, but that might not work so well either. In the end, I think I'll mask off the area so only there serrations show, fill them in with JB Weld and then use an old gift card to scrape it off, leaving only what's below the surface in the grooves. That should make it fairly smooth.