After gluing the cores to the tubes, I filled and sanded all low spots. I then cleaned up and prepped my building surface and reset the saw horses to very that everything was sturdy and level and straight. Following the book I laid down grey tape and made my measurements. I screwed some scrap wood to the edges of the surface to butt the leading edge of the tubes against and tack glued the elevators down, making sure I had a left and right and marked the top of each. I trimmed the cores to the required chord. Some parts of the cores were a little short but nothing to worry about. Cutting the strips of uni to the required size took some effort, but a large cardboard cutting mat my wife had from the fabric store helped as it had a grid and a 45* angle premarked.
The layup went smoothly. Letting everything cure for a day, then I will pop these loose, trim and lightly sand, then flip over and do the bottom.