Upload some pics of the interior of the transom. Rigging and such. I'd like to see how you did everything.
Slow going, but that’s how it gets done right. I drilled the tunnel tab brace holes through the transom a couple nights ago...the overdrilled to 1/2”, mixed up some epoxy thickened with cab-o-sil and microfiber, then filled the holes. Re-drilled them this morning, cut some studs from 5/16” stainless allthread. Had to re-tap 2 of the bases and time Sert the other 2 because the threads were on an angle. Use pipe dope on the threads, clean off everything else, then 3M 4200 to seal to the hull, washers and flanged nylocs. 4 fasteners and holes, 5 hours all in. Lol.
I ended up having to do some "spotfacing" over not flat surfaces and what I found that worked very well was a simple die grinder stone. Whenever I buy die grinders at harbor freight half of 'em come with a handful of stones. I found one that looked like a 3/4" round by about 1/2" tall disc. With a straight, 45°, and 90° die grinder, I could get just about everywhere I needed to and the stone cut like butter to give me nice flat surfaces for the washers/nuts.Keep at it man!! Slow and steady! I've got a ways to go to catch up with you. I just put another bulkhead in this week and have a ton of glass work still left to do. I know what you mean with the tabbing making the surfaces uneven. I'm trying to keep everything clean and ground as flat as possible so as to avoid that same problem.