I only welded every 4-5 inches on the inside of the trunk lid. When I get the topside where I want it, I'm going to use sealer around the edge like the factory did, no one will know, except for members here. If you look through my entries on this thread, I had a bunch of problems with my driver's door. If I could offer some advice:
1st - replace or rebuild the door hinges/pins before doing any fitting of the door(s) to the body
2nd - buy a long (like 4 foot long) straightedge
3rd - start from the rear where the door meets the quarter panel and work your way forward.
4th - don't expect the fit to be that good on all gaps - the cars weren't perfect to begin with - I still have some gaps that will need work on the driver's door
5th - take your time