I agree with the non-standard idea. It doesn't seem that Hobie ever used any methodologies to standardize hole placements. Mondays here, Tuesdays there, etc. etc. It would have been nice if the Frame castings would have had an indention for a drill guide. But, this may not have been enough. In any case you indicated that you had another boat. It might be possible to drill out the rivets on the frame castings and swap out by re-pop riveting the 82's to your present boat frame. If this won't work, then you'll need to find new or undrilled corner castings for the 82 hull.

Then the problem becomes where to correctly drill the new castings, since they cover the holes in the pylons.

Good luck.