I don't have a recommendation unfortunately. But I will endorse your decision to let the pros handle this job. I welded in the real steel patches my front doors... I tried to keep the heat down, but since you can't really get in there to hammer out the welds to combat shrinking (it's tough to fit your hand inside the door to get a dolly on the back side), I ended up warping the crap out of the outer door skins. I then spent days cutting out the big flat area of the door, trying to get it right, and welding in a big patch VERY CAREFULLY (i.e., compressed air in between every single tack weld) and only made them worse. Then I spent 3 or 4 ful ldays trying to fix it with body filler, which ended up being way too think for my comfort.
Now, I have given up and I'm planning to just buy fiberglass doors from Gozzard for $3k before shipping. Huge huge huge waste of time and money. So yeah, take it to a pro. You might even consider having them use a backing strip and a panel adhesive to attach the big flat area on the outer skin.... the welding and grinding heat really can ruin the the whole door- trust me!!!
I have personal experience that if you talk to the head instructor for the auto body repair program at Pierce community College in Tacoma, you can get your rig done by the students for materials cost only. I personally saw a: 1968 Camaro get done, a 1970 GTO, and a 1970 Chevelle get done and the quality was decent. cost for the GTO was 3k and that included trunk and at least one rear qtr panel.