I can tell you this. Not adhering to these precise measurements will throw off the gap between the lower radiator support and the front crossmember. This gap is what dictates the alignment height of the front fenders.
I slight error at the cab mounts will be magnified exponentially at the front crossmember, leaving you with no way to make the front fenders fit right.

1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission