Hi Dave,
I'll have to try that. In the meantime I had figured out that if I make the mortise on the "flat" side, and then create a surface on the inside and push it all the way out on the back, I could then draw lines around it where it intersected with the leg, delete the protruding piece, erase the lines, and then delete the surface left on the back leg...
But you also make a good point about the downward forces on the legs and that I probably don't need to angle them at all. Although this has been a good learning experience
Thanks for all the help,
Rob