Made a bit more progress, I won't swamp the thread with pictures, I'll save that for a project thread
I tried with hand tools, and after cutting 2 mortices which took forever, I really wasn't happy with them, must be an OCD thing. Because I have 16 to cut (2 tables now, each leg has 2 mortices), I went with the router and a 1/2 bit.
A few errors through carelessness, but I had enough blanks cut anyway.
I then got excited and thought id try a test tenon on a scrap of the apron material.
Went ok - I used the table saw, and crosscut sled to cut the 2 small sides with the same blade height. Once they were done, I cut the bottom, and then finally the taller section at the top.
Corners cut with a chisel, and then files/sandpaper to round. The leg I was working on is a perfect fit, tried in another, slightly loose, so im assuming that I will have to fine tune each tenon to each mortice , perhaps put a mark on the end of the tenon and inside the mortice to show which mates with which?
Shoulders look a bit rough as I went at this with a file, won't do that again, or will at least take a bit more care! (that's what test pieces are for right!?!?)
All in, its a decent fit, so has spurred to me on to do some more when I get some more time, will take my time, and cut each one to suit each end. I think im expecting perfection, and all the tenons to fit all the mortices!