Dear Jerod,

There should be no contact between the back of the brace and its housing whether cut at 45 or 90.

When using deep braces like yours in compression the braces will deform inwards and outwards along the thinest section axis and will not push against the back face.

Generally when a long mortice slot is cut this would be provided with a tapered rear housing face.

Small depth braces can be fitted to 90 degree mortice because it is more difficult and quite time consuming to cut a sloping shoulder into a very confined mortice bottom.

To answer your question about peg numbers to be employed would really require that we have a better understanding of your frame layout and also be able to run some numbers on the analysis programme to see just how heavily loaded the braces are in tension.

Using 2 pegs will move the brace from operating in a simple "pin" connection mode to "moment" connection mode and this will improve the frame stiffness.

You are hopefully now beginning to realise why the services of timber frame engineers are sought on larger non standard type frames where getting this kind of thing right matters more than on a building the size of a typical Jack Sobon style garden shed.

Regards

Ken Hume