Good document .. but I those 'housed' or 'tennoned' joints are too
complex for this job.
The strength in this job is being provided by the steel plates ...
just need a way of 'stopping' the leading edge of the 45 degree brace,
maybe I just have to cut the end timber of the brace to 50 degree
rather than 45, square off the point and try and scribe in this to the
post.

Just wondred if there was a technique to doing this.


Just mark the joint out carefully on the three sides of the post, score all
of the lines with a straightedge and box knife, then use a skillsaw to cut
the square shoulder. A few minutes with a sharp chisel and a mallet will
get the rest of the waste down to the lines, and you're done. It's not
rocket surgery.