The Cross House
It is not hard. I take three at a time and cut the curve with a jigsaw. Then I smooth them with a disk sander.
I have to buy a bundle of shingles and then pull out all the shingles that are 5-inches or more wide. The narrower shingles get used for shims. I now have enough shims to last the rest of my life.
Bit by bit, I will continue to make curvy shingles and, when the weather heats up, I can return to the south facade.