Definitely remove the striker from the cab.
Put your focus on how the door fits the opening at the rear, from top to bottom, with the beltline matching spot on.
Once you have that, get the rocker panel tacked in. This is VERY important. I refer to the door opening (lock pillar, latch pillar, rocker panel, and top of the door opening) as "the ring of death".
If you do not have that right, you are dead.
You need to think of cab restoration (especially with this much panel replacement) as starting with the doors, and building the cab around them.
Carl
