OK since the fenders were bolted on we were lucky that not all the bolts were installed so I used those as landmarks
IMHO you will need allot more measurements to make sure all the panels are square - Not really experenced in those tasks - rarely need to replace any of them on the cars I've owned. Hope this helps
A= 40 1/2"
B= 30 5/16"
Note that A is measured from the front edge of the rear most hole to the inner fender hole edge visible through the radiator support hole.
B is taken from the forward edge of the rearmost fender hole in the inner fender, drivers side, to the rear edge of the hole just in front of the VIN location