I gotta go old school for advice here fellas, the best bonding method is to weld. The better welders will take 230v. The sheetmetal can be gas (oxy-acet) welded and that is a very ggod method for doing skins etc. Don't overlap the skins, butt the edges in a very tight fit and weld without filler rod. Filler rod can be used to tackweld, but once you start rolling the puddle you shouldn't need filler.
Your door is 19ga, i use 18ga - close enough and easy to work with. Start doing your homework and practice, theres lots of talented folk on here and we can let you know what is going wrong. Learning to weld sheetmetal is one of the most difficult things that you can do in the restoration of a car and it ain't easy to learn. But you can do it. Welding the sheetmetal and hand finishing it was how it was done back in the day and nobody has improved on it. If you take the time to learn the metal you will gain respect for it - get Frank Sargents book 'Metal Bumping', written back in the 40's maybe and it is pretty much the bible on how to get done what you want to do.
Good luck and keep us posted on progress, if you need examples etc ask and we'll fix you right up.
Merry Christmas, oj