Completed everything today (except for the stuff I need to do in the spring) and wanted to share my approach to a leak free wing and deck plate. I used the same stuff 5+ years ago and never a leak.

Dum Dum strip Caulk by Proform. The box should last me another decade
I applied it around the deck plate and at the base of the stanchions. I also replaced the small rubber o-rings.

I also applied a small piece behind the seams to ensure a solid seam. This stuff is NOT an adhesive. It’s like plumbers putty. It doesn’t get crazy hard and it’s easy to remove.

when you tighten down the deck plate, this stuff will compress and take up any irregularities.