Just had a chance to work a bit on this. A bit of tedious work, bit but needs to be done if I want it right.
Want to actually bolt the front part of the door in place so I can set the door gaps before deciding how long it needs to be made.
To find the best hinges I clamped them to the table and pushed hard one way and then setting the square in place. Then pulled away from the square and measured any gap. Got two pairs that were only 1mm to 1.5mm total movement at the far end away from the pivot point.
I had a problem that the front gap, even at maximum adjustment, was too tight as only 1.5mm-1/16" before primers and paints. It is not like a 50's on vehicle where you can move the front guard/fender forward to set the forward edge gap.
Another thing I noticed there were low and high spots stopping the door from being perfectly flush along its entire length.
So I cut all the way down the edge of the panel so I could solve both problems at the same time.
I lifted the low spots until perfectly flush with the door.
Also set the door gap to 3mm-1/8" which is the minimum recommended on bare steel.
Continue to set the gap and make sure it was flush all the way to the top.
Checking for flush after tacking.
Welded it by 'tack stacking' all the way in one hit without stopping. Very little distortion as the HAZ was kept small and even. Let it cool naturally as using a air gun or water only hardens the metal leading to cracking and uneven shrinkage.