Hi Dre,
To a degree, I used the measurements offered in the service manual. This frame took some abuse. Up at the front, the two long rails were pitched like this� \----\ (standing at the front looking toward the rear)
The long rails were also bent about 1� toward the passenger side.
Per the measurements in the manual, the rear of the frame was still in original undamaged condition, so I was able to use it to fix the front.
I used everything my shop could offer. String lines, levels, plumb bobs, bar clamps, crow bars, Kubota tractor, framing square, breaker bars�you name it�it was probably involved.
I also have a Willys with an undamaged frame. This was helpful when checking measurements.
That said, I�m sure your 3A Page brethren (including me) would be able to help you with �on the fly� measurements if and when you might need them.
Tim