I welded a 1/2" nut in the center of a 6 1/2" round piece of 1/4" plate and welded the pipe to the plate.
A piece of 1/2"all-thread was threaded into the nut. The brackets and the air springs go together like this.
The top bracket was bolted into the upper spring pocket of the frame.
The pipe registered on the upper spring mount and the all-thread went through the upper shock absorber mounting hole.
With the lower A-arm blocked up to ride height, the distance between the bottom of the plate welded to the pipe and the top of the new lower airbag mounting surface was measured. Then the pipe was trimmed to give 6" between the two. 6" is the front air bags' ride height installed height.