Which first??

I have already notched the rear of the truck and am about to install the bags and four link. Should I install the front bags and spindles first or should I bag the rear end and install the four link.?

Also how do I determine and set the ride height. Im new to the 1 ton dually scene

what year model dually is it? if its a box style you might have to Z the front to lay flat but since you have notches in id go ahead and lay the front out before i welded up my rear link bars and bag brackets....ride height is gonna depend on what all is done, tires and wheels, and personal preferance

its a 1977 camper special. Another question is there a trick or possibly some kind of jig to keeping the rear axle square>