Hard line questions

[NZSquare]

Hi all,
Next project for me over the coming months will be hardlines for my truck, its an 82 longbox with bags on all 4 corners, 1 tank, EDC and electric backup compressor and an accuair vu-4 for brains.

I want to hardline the whole thing if possible, I have a bit of time making lines for aircraft but am not familiar with commercial stuff. My main questions are:

- I want to go stainless, is there a better (more workable) option like marine ali tubing or something ?

- wheres the best place for fittings ? I'm in New Zealand so will do a bulk order, I was assuming Grainger or somewhere like that

- Should I go to pressure sensors/digital gauges to save plumbing all the 1/4 line for the mechanical gauges ? I dont really want a cheesy lcd air display unless it can be hidden.

- Any other words of advice ? I know I need to get a 45 degree flaring tool and have a hand bender, the system lines will be 3/8 (-6)


Thanks