Looking good so far. Glad my build helped and inspired you.
Do you need to end feed sheets into the machine? If so the 45deg braces in the corners of the open end - one end could be deleted and a single horizontal connection made between the upper steel sections instead. Stiffness would still be good be access improved. Depends how you want to use it.
Also will you drop long bolts through the steel upper section as per my build? I made custom thread inserts which ran in the lower extrusion for the bolts to go into. If this is your first machine can you make these?
Also this needs clearance holes in the upper section for the bolt heads to drop through so draw these in to make sure they miss the rail fixings.
Good luck with it Kieran !