I decided to drive to Skybolt in Leesburg (3hour round trip and worth it - what an awesome facility) and picked up some additional inserts and magnets. I had found that using a light under each one didn't work because the gelcoat was too opaque. So, after taping the inserts, with magnets installed, to each of the flanges, I then placed the cowling on the plane, aligned it and secured it in place with Gorilla tape. Good stuff. I took another magnet and placed it near the where I thought the insert would be. Those magnets are STRONG and found the lower magnet like a bat out of hell. The idea was to mark a few dots around the magnet, find the center and drill a #30 hole and cleco the cowling to the insert. But rather than estimate the center of the insert I took a template and drew a good circle by connecting the dots. I tested this location once or twice and each time the magnet returned to the same spot. Then I took the square template, centered it and marked a square around the circle. Then connecting the corners I drew a line from opposite corners and the intersection was the center where I drilled and added a cleco. Worked each time and then I moved on to the next flange. I ran out of time, so I'll continue this tomorrow.