I did this on my seafari.
My first goal was to put some melamine on the outside of my transom to give me a surface to work against. It didn’t work out so good for me. It sagged and I had tons and tons of grinding and fairing.
I did lay up bigger layers as I went. I put 2 layers to entirely cover the “new” transom and tie it together. On the exterior i did put some peanut butter on and epoxy fairing. You can’t tell know but it was a real mess. Make sure you do tap test around keyholes. I had serious delamination.
If I could do it over I would find a way to really secure the melamine on the stern and make my smaller fillers and then my over lays. I have pics buried somewhere. I’ll post for you for good and bad. I hope someone can chime in to help here.
