I asked that question earlier and have been thinking about this - if you're going to clamp melamine or formica covered plywood as the "form" against the rear of the transom, I might suggest cutting the sides out leaving 2" like you did at the bottom. Reason being is you will be hanging full width cloth across the transom and those "wings" don't do anything for you, you'll be laying the cloth there anyway. Have you really decided on full transom vs notched?I want to advise you that, if you're like me, you can overthink this very easily and waste a lot of your time doing so - I spent days and days staring at what I was going to do, like in a chess match, out to the nth move. It's ok to think through what you are going to do but my advice is to break it into small manageable chunks. Like in this case, get the dam on the back of the transom and get 3 layers of 1708 in to make your new flat transom. Once you've done that, scruff that up with a 80 grit flap sanding wheel on a small grinder. Then plan your next step, i.e getting the core cut, laminated if more than one layer, and then how to clamp it in.One step at a time or you'll get overwhelmed and lose precious time.
That outer skin came out nice. Question, what are those white spots on the coosa? When I bought mine, I got a big discount but there were some imperfections on them that looked similar to that. Turns out on mine it was a bit of extra mat mixed with some paper that must have rubbed off during manufacturing. it was all on the outside so I just took a grinder and cleaned it off and they were good as new. I did a test laminate on a small strip before I sanded it and the glass peeled right off in those spots. That may not be the case with yours but I wanted to make sure. Would hate for you to run into issues down the road.
Meaning the bottom of the core? I always bevel that to match the hull angle, the less gaps the better. The big thing is make sure theres not a hard angle on the outboard side of the core in that bottom corner there, round it over just to prevent problems of it not letting the core suck all the flat to the skin at the bottom. Hard to describe.... The gaps in the pic dont look bad at all though!