Adding nutplates only a few at a time allowed nice ultimate alignment and allowed us to learn how best to accomplish task.
Seems no matter how careful you try and drill a perpendicular hole in fin with hinge outboard, there is a slight misalignment.
We found instead of drilling from .125 to .187 in one shot (when hinge is inboard held in place with clecos), drilling in 3 stages yields better holes with closer tolerances.
2 holes in lower fin got screws with hairspray on them and JB Weld KWIK to bring back nice fit after drill made an oval when tried to drill in one shot and drill moved sideways a little when it contacted hinge with hole in aluminium slight out of alignment.
Y9-05-15