Loosely set the fenders and hood and see how the gaps look.
The hood to cowl gap was tested using paint mixing sticks that measure just shy of 1/4".
The right fender to door is a little tighter than 1/4".
If you are able to get the gaps even like you see in the last picture, you can start plug welding the fender aprons to the firewall, the frame rails to the torsion bar crossmember, etc.
The fender to hood gaps will tell you if the front end is square.