Here's how I mount the doors after mounting sidepods, rear panel, and engine cover.
I mount the striker support up against he body, snug the bolts in the middle of the slots. Hold a bright light behind the bracket so you can see through the fiberglass and drill the holes in the middle of the slots.
you can see the print through in this pic.
I mount the latches directly to the frame and countersink the screws. Latch the door frame to the striker and mount the hinges. Adjust the height of the front of the door frame to .250" above the sidepod, then tighten all hinge bolts. The door frame should now swing open and closed easily.
You can see 2 out of the 3 bolts holding the latch on in this pic.
Trim lower front corner off the door skin so the door can swing without the skin hitting the sidepod.
Now put a piece of masking tape along the edge of the door skin where the striker will go. Cut strips of regular cardboard and lay in the gap between the door and sidepod.
Door open, I use strips from the bottom of striker to the front of door (only one piece shown)
Door closed
Slide door skin into opening and tap on skin to mark on the masking tape where the door needs to be slotted for striker. Measure and mark door skin to allow for the complete striker to clear the skin. See pic 3 above.
Drill two 3/16" holes in the door frame as shown by the two 10-32 screws in the below pic.
Slide door skin back in on the cardboard shims, make the back of the door flush with the sidepods and drill top hole only. Install countersunk 10-32 screw in the top hole and tighten snug. Close door and recheck that the door skin is still flush with side pods and drill lower hole. Install countersunk 10-32 screw in the bottom hole and tighten snug.
On the top front of the door skin, drill the hole for the mirror mount so that edge of the skin overhangs the door frame by 3/16" and install a 10/32 screw. You will be using a different screw for final mounting, the 10-32 is to use until final mounting. Adjust front lower edge to the desired position and mark the lower frame to skin. Unbolt the 3/8" bolts and remove door leaving the hinges in place. Drill the lower hole in the skin and install the countersunk 10-32 screw, you will want a countersink due to the very limited clearance.
Install front door aluminum, mark and slot aluminum for 3/8" door bolts, install bulb seal on aluminum and final mount it to the door frame with rivets.
Install complete door back on the car with cardboard shims in place, the 3/8" bolts. Remove cardboard and fine tune hinges for smooth opening if necessary.