After a bit of a lapse, it was good to get back on the project again. Last week I placed an order from AC Spruce which included some bushing material to be used as a drill guide for the 5/16" bolts. Unfortunately there was a shipping delay and it doesn't sound like the items will arrive for a few more days. So I did some scrounging and found some tubing that could be made to work. This tubing had survived a garage fire years prior but the heat caused it to sag and bend. I just needed to find a couple of sections that were straight over a few inches. The sections that I found, I sandblasted to get the outer scale off and then mounted in the lathe. I drilled them out to the required inner diameter and then turned them to the required outer diameter. This allowed me to insert the sections in the 12 mm ID tubing on the welded frame and use that frame to drill the 5/16" holes.
After careful layout and marking I was able to drill the critical holes for the landing gear and then finished up the 12 mm holes for the remaining spar studs.