I finished match drilling the fuselage join and so countersunk the longerons and the shim at the rear of the baggage door opening. While I was at it, I countersunk the right mid-fuselage deck, which I had been procrastinating on. Then I removed the top skin to countersink the shims, only to find that the one on the right side did not fit well. I modified the shim as shown in the first photo and then re-drilled it and counterunk the three rivets there per the instructions. Finally, I used my recharged Dremel to open the skin for the right step and fit it in place.