Machined an SS drift punch to .311.5" which fits snug into the 6 wing spar mount holes to center pop the plates. Then I machined down some aluminium rod to the same diameter and bored out the center to match a 7/32 drill bit because it was band new. Inserted the drill guide into the spar bolt holes and drilled steadilly. Then I drilled the holes out on a drill press with 9/32 allowing the drill to self center. Then I checked the plate against the spar. All was well so back to the drill press and drilled them out to 5/16 and the alignment was perfect to the thou.
Did some solid riveting of which some will have to be redone to meet quality standards.
Stepped up the root doubler 3/16 holes to 1/4" as the rivets have left the holes over tollerance. Consent was sought and recieved from Mathieu Heintz fot this change.
tools I made in my shop to make my life easier when drilling the 5/16 spar holes to the new doubler
Couldn't have worked out better
3/16 mount holes are being enlarged to 1/4 for AN4 bolts