I tried to keep everything that was relatively solid rather than removing the battery box for instance.
I added that little bit of flange just to stiffen things up a bit. Seemed like a good thing to do.
Not having the L brace would increase the end-to-end gap in the floor support by a bit, as well as making the step that you posted about too large. I think the L-brace should still be used. I fabbed up new ones because my originials were rusty and cracked, especially right at the spot where the cab support welds in.
