Got this idea from reading the zenith.aero blog from Quality Sport Planes about doing the XL upgrade.
"Sharon is removing the old paint around each rivet hole. This was done with a paint removing tool Doug made by welding a nut onto a drill bit which is loaded into the drill upside down so it does not cut. It worked quite well. We called it the paint twirler (as in, "ok who has the paint twirler now?"). It got used a lot!"
When I frist read this I thought it was over kill but I mad a couple just in case. It came in handy putting the new rivet holes in the upp and lower spar cap angles. Actually ground a taper on the end that goes into the rivet hole. It burnishes the paint away and allows the rivet head to set against the metal.
I had Jim do the extra rivet line, the 40mm spacing is now 20mm between the frist 5 ribs.