[RidgeRunner]

I found putty next to the factory skin on my 1983. I did the putty and transom clamps on mine. I used matt on hatches where the skin was laid out on a work table and the core and skin were perfectly flat and it worked great. The transom is anything but flat on the Wellcraft so putty is easier IMO. Both ways will work. Laying glass in the corners of the transom where you still have a little of the inner skin (due to the floor being in the way and such) will prove very difficult. Putty could be easily troweled into tough spots, fabric can be used to laminate the plywood together for the core. I made a three piece transom out of core material because my transom had such a curvature. The wings were laid first and the overlapping center core was clamped in place last. Putty was oozing out around the perimiter everywhere. Put the gloves on and wiped the excess with my finger (like it was caulk) to form a radius on all the transitions (filleting). After it kicked it made laying the inside skin a breeze. I did the same across the top of the core because I made the 83 a full transom where the core stopped a few inches from the top of the transom. You need to add quality fiberglass to the places you intend to extend the transom height. Fairly critical because you are going to be hanging the motor from that area.
Single scarf ========\ \________________/ /===============

BEST Double scarf ======> >=============< <==============
Double scarf requires work inside the hull before adding core.

Google scarf joint for a better visual. The stringers look gone at the stern, what about the rest of them?