shaving back wall

hey do you guys frame out the back wall when you shave the back of the cab or is the flat sheet strong enough? im using 16 ga

when i did mine i braced the back wall from the inside with 1x1. 1 peice goin horizontally along the top, and another peice going horizontally along the bottom. then i put an X from top bar to the bottom bar. from there just cut out the back wall, make a template for the new peice, trace it, cut it, and then weld it back in.

heres a pic i found of mine, didnt find a pic of the bracing though...

what did u connect the braces to and how?