I pulled the trigger. Finally. (OK, 3.5 years in design is might be a bit much). I purchased the 3x5x.375" beams for X and Y. Wow, those are heavy! 95 lbs for each X, 65 for each Y beam. I think that is that last time I will move the beams by myself. It's one thing to say "Yeah the gantry will be 200 lbs". Now I have to get serious about how to move it around to work on it.
I measured the beams for actual size of the corner radii, flats, and inside dimensions. I then updated the drawing. Next I will make the models for all of the water jet parts. I have also been researching diamond core drills, water swivels, and inserts. More on that later!