Thank you Tom for your constructive comments.Well done Hombre 3am posting this thats dedication
It all looks ok and obviously works for you just a couple of observations
(A). Its best not to have any flat surface on the bottom rail and the bevel to extend the full length so to shed water
(B). And you may fined that if you extend the part marked as Y so as to reach the bottom of the rebate on the top and bottom rail and then having reduced the top and bottom rail in thickness to accommodate Y then glue the top and bottom rail to Y will result in a stronger joint.
As with all things always several ways to do a job and as long as we finish with what we intended to make then who is to say its wrong its just a different way of doing it.I thought long and hard about how I wanted to do things and feel that I reached a happy workable compromise. I would like to think that you appreciate my decisions, even if not actually go as far as condoning them.