I've got an essentially 1 1/2" square piece of wood 3' long with one corner running about a blade width outside the core of the tree: the growth rings end square to the surface on two adjacent sides. It's pine but about as tight grained as you'll fine and it used to live in the bathroom wall of a '70s build house.
I want to cut a rectangular notch out of one corner the length of the board, about half way across one face and a third of the way up the adjacent face. From the end of the notch (on the side about a third of the way up) I'll cut across to the corner opposite from which the notch was taken out. The cut across won't be flat but on about a 12.5" radius, so not far from it. I'm going to be gluing a bent piece of 3/16 plywood to the radiused edge that's going to have some spring back left in it. There will be plenty of solid radiused support at the ends and a couple of ribs along the way to help hold the curve.
My question is which way do I turn the end grain before I start notching?