Bulkhead/tub setup

Good morning eveyone. I am looking for some advice how to set up my bulkhead to tub alignment.What is the best way to set up the fixing of the tub and bulkhead as I have a new chassis and galvanised bulkhead and I am starting to reassemble these back on the chassis but unsure how to start.because the tub has rubber packers under it,and need to get the correct door gaps ,and body alignments So really need a reference/ datum to work from or were to start from. Thanks Steve

I would level the chassis with a laser level across the mounting points so you can use a level to get the bulkhead and door jams vertical. You could use window packers and put the front panel, wings bulk head and tub on loose then work it to get the doors to fit. If you tighten from one end you could run out of clearnce by the time you get to the other end. Once you get the packers right you can slip them out and make up the correct thickness

Back body on first
Bulkhead next
Doors
This will give you the gaps. You can then pack the bulkhead to decrease gap. Also using the hinges for line fit.
Then put sills on ,these can then be shimmed.
Good luck