I just spent a bit tightening and squaring the frame.
The Z axes don’t center on the uprights. They should tend towards where the bottom is. This is probably best done after you install, unless you’re really confident. When centered, The X and Y rail cars touch them, and it looks like the parts that hold the X rail will completely crash. Pushed down a couple of mm and it works, and I think the Z motor mounts still get close enough to the top.
I was a little worried that I should use corner braces on the bottom X extrusions, but it’s easy to get a square in there without. Makes it nice.
I might consider an extra set of braces for the back Z rail. Looks like not.possible for the front 2, though. I get a little movement on the back rail, maybe because of the V slot extrusion. Well a little torque will probably manage that once I’m sure that the rail is properly centered.
I have left no real provisions for mounting the control board. Since I’m not using the SKR Pro, I didn’t print those pieces, so if someone does some real documentation, should probably include that. At some point I see I stopped adding parts used, and I think I missed several mentions of the M3 slide nuts. 
well, it’s supposed to be a project log, not assembly docs, but I was halfways trying to do it instructions style. There is a good reason that I write code and not procedure manuals for work…
Now to order another bag of M3 screws.