don't try to leave the roof in one piece with the a pillers laid back. the windshield won't like it. 53-55 trucks have funny shaped door gl*** that gets worse when chopped. chop the front more than the rear to square up the door gl***. they look much better. on any chop, it is better to tack and eyeball than just measure and cut and weld.
thanks Guys for comment I thought not to cut the rear window, to cut the part under the gl*** 3 ", lower and tilt the cab A pillar, there are many ways to chop the top I would avoid cutting the roof into 4 parts.