Next step: WELD EVERYTHING
I started by filling in all of the pass-through joints in the front and rear plates, adding a bead on the inside faces each time
No shame in using flux core, guys. Don't let anybody tell you different.
As a rule, I made sure everywhere that two pieces joined was either fully welded or had 3 welds minimum.
To give you an idea:
I only drew on the welds that were visible in the pictures, so you know, extrapolate.