Steve Frederick method of hatch??

So built my frame walls out of 1 x 4 material. I got the cut for the roof splines. But the cut for the hatch I am confused.
I am using 3/8” plywood on the outside, then aluminum over that
Cutting the pieces from each side not sure how to cut that the “Dan rambles” videos show him marking a it 2” and the curve at the hinge, but besides hoping you can cut with a jigsaw that perfect is there a better way?
Also
Questions
Do I put the 3/8” skin on before cutting these hatch pieces?
It seems he puts an 1/8 piece on the inside as well?
I got the Frederick Manuel and watched the dan ramble you tube. But it’s like both skipped Thur this so fast
Thanks for any help
I am using 3/8” plywood on the outside, then aluminum over that
Cutting the pieces from each side not sure how to cut that the “Dan rambles” videos show him marking a it 2” and the curve at the hinge, but besides hoping you can cut with a jigsaw that perfect is there a better way?
Also
Questions
Do I put the 3/8” skin on before cutting these hatch pieces?
It seems he puts an 1/8 piece on the inside as well?
I got the Frederick Manuel and watched the dan ramble you tube. But it’s like both skipped Thur this so fast
Thanks for any help