I would like to emulate your heel transition in one of my future builds as I am sure it makes playing the upper register much more comfortable. Would you be so kind as to detail the fixing? It appears that you have cut in flat for a washer, will you then fit a pan head screw or do you use screw cups/ferrules with countersunk screws? Have you ever used the threaded inserts with machine screws? Your rebates seem quite large, I guess to spread the load as much as possible. Is there any potential weakness in not using a clamping neck plate?
Sorry to pick your brain but I do like the look of your neck join