Rear quarter panel, upper/lower and tail light housing question

[Fur_Pig]

Hey guys,

I am a fairly experienced fabricator and decent body guy but building my first EB and have some questions.

I have a fairly rust free tub that was on a race truck and needs a bit of panel replacement. They welded the vertical body seam the entire length from rear quarter panel to the tail light housing. I have replacement sheet metal from wild horses but since I plan to do upper, lower quarters and rear tail light housing, is there a "easier" way to take this apart in a chunk and reassemble as piece parts?
Any tips or guidance is much appreciated. I have sand blasted the tub so spot welds are detectable to drill out.

 

[Rustytruck]

My understanding ford used to weld up the whole side as one assembly and then mate the assembly to the other parts on the production line. use to be able to buy the side assembly from Ford. I have never seen this in my life but I no doubt believe it to be done this way. what few replacements I have done were all done peace meal. I have never replaced a corner post but that looks extremely hard to weld together given the access you have.