As far as design goes, its time to flesh out a couple of joints that have been troubling me. I really like the idea of using common rafters on the lean-to section of the roof (the roof covering the porch). The main cabin has a roof pitch of 9:12, but the lean-to roof is shallower than that. My design shows these common rafters attached to the continuous top plate, but I never drilled down into what the joinery would actually look like there.

My initial thought is to use an angled, shouldered dovetail tenon on the common rafters. The whole tenon is 3" long, and the shoulder is 1" long. The rafter tenons would join with mortises cut from the top of the top plate.

Any thoughts?