How to transfer lumber cut with odd angles
I've tried a few cuts like this and got one of the crazy devices shown below. It's a "multi angle measuring ruler". Even if you get the angles right, you still have to cut the wood accurately and that requires a good miter saw, and even then, be prepared to do it a few times to get the saw set just right. This is an art and it takes a lot of practice It's not as easy as Norm makes it look on "this old house'. Good luck.