Measure, fit, tack, and measure again before committing to the final welds. Be sure the cab is square and level before doing any kind of permanent installation, including checking the fit of the door(s). Discovering you've created fit problems with other components by getting in a hurry to install patch panels is a huge problem. Good luck!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!