Your dowel treatment is what I do on all externally stressed feathers. Prevents the attaching hardware from crushing softer balsa . Not much more difficult unless the balsa structure is too soft to let a Forstner bit cut a clean hole. I've used a Dremel and bit with success but only before the 2nd cup of Joe.

The attach point is well out there. All Fleets attachments were about 2/3rds of the span outward.

Currently re-engining my Cub and trying to repair my Fleet. I'm so far behind. Our Club fly in is this Sat and I'm rushing to get the Cub done. I need to get a job so I can find time for my planes and a thorough garage cleaning.

Ray