[GradySailfish]

As John B said, you can leave the core out of the boat and glass the 1708 over the entire core outside of the boat. Once that has cured you can them install the core into the boat. I would use the paste, but only around the perimeter of where the core will sit, i.e. around the sides and bottom, bot fill the voids the best. However, insteado of spreading the past all around the inside of the transom skin, I would instead use wetted out 1.5oz matt, as I think it will give a stronger bond. Either way though you should be fine.

Once the core is in, you can further secure it (glass it in) by using 12 inch wide pieces running from the top of the top cap to the bottom, along all of the edges of the core. I would first apply the smallest pieces of 4 inch, and gradually work up to 12 inches....4,6,8,12.

This hard to put in words lol, but I hope you get the idea.