Cab floor replacement order

[KMC3420]

Hello, I am to the point where I will be replacing my cab floor over the next few weeks. I have the cab braced and have removed the outer rockers. Also, I have drilled all of the spot welds at the rear cab wall. I still need to remove the spot welds on the footwell flange. I am wondering for anybody who has done this before did you pull the floor and align the new floor to the old A and B pillars or did you replace the lower A and B pillar sections first and then install the new floor? Below are the pieces I am needing help with replacing before or after floor install. Thanks.