Give me some direction - 4200 around the bolt holes? Small bead around the perimeter of the backing plate?

I did a small bead around perimeter then around bolt holes. Then filled bolt holes pushed bolts in. Then filled around bolts on the inside and tightened.

All of the above and then some to be safe. I did rather heavy around the bolt holes however put a couple coats of resin with Qtips in the transome mounting holes. Stay about 1/2" or so away from outer edge of mounting plate if you want to eliminate clean up. On the other hand it's nice to get as close to edge as possible though just to eliminate debris etc from gathering where there is no sealer. Pretty much just like you said. I also put a bead around the bolts where protrude through on the inside so the washer would seal up against transome. Btw a tube is plenty for both sides. You can alaways put a small bead around perimeter of plate after installed if you care to. I removed after less than a year with 4200 and wasn't a fun time. I literally hooked athe chain fall around the tab and lifted the rear of the boat off the trailer and still would brake free.

Next time get plastic cabinet wedges, just start 2 and then take.032 safety wire wrap it around 2 handles of your choice and make a safety wire saw to slice the 5200 or 4200. you won't lose and gelcoat and no need for the truck. and yes you can get it around the thru hull fittings.

i'll vouch for the above method !

You're scaring me. Is 4200 too strong? Different product recommended?

I use 5200

I don't have the balls for that!!!

I use to be in the automotive glass business business for several years. Btw op 4200 fine to use. Many of us on here have seen used tabs with gel that has been pulled off with plate. I'd use 4200 again however just making a point how well it bonds.

Posts #2 and #3 are spot on.