Humble Beginnings - For Alu

[EddyCurrent]

I think it's not so much the metalwork that needs lining up but rather the support rails upon that metalwork. This is where the epoxy method etc. comes in to play, obviously the metalwork needs to be rigid so welding might be a good idea for some of the parts anyway.
Maybe you should have a look at some build threads that have been posted in the last 12 months, you might get some other ideas.

[Blackrat]

weld without a doubt ...

those bolts if overtightened will crush the box section .... and even if they are torqued up right, with vibration the frame will flex causing the bolts to come loose (admittedly you can lock tight em in)

id weld it up slowly, then epoxy the face