Thank you for your post. Wasn’t sure anyone would answer 
Yes, it seems quite complicated, I want to keep mine much simpler.
I’m interested in the measurements for the beveled insets (height, width and depth) and one of the short sides of the frame so I can get an angle approximation of the fitted CMC’s.
EDIT:
Ah, now I see, hadn’t seen this YouTube video before:
So there aren’t really any “slots” just a big hole and a few supporting ridges and a big supporting plate.
If you could provide me with the measurements for the big hole, the supporting plate (and it’s distance from the front opening) as well as one of the short sides that would be enough.