When placing the mount against the main wing spar you come to realize it doesn’t fit flush. At least mine didn’t. Mostly because the holes in the mount are suppose to line up on top of rivet heads on the main spar. Some holes are bit off. I don’t think I would have had an alignment problem if I had reversed the rivets on the main spare. Oh well.
I expanded the holes only in the direction needed with a small milling drill bi and small sanding drum. Then made sure to round off the hole corner.
