Of course, I'd like to see anybody who gets into all the trouble for a roof, do it all and be done with it. I opted to have ours done "commercially" and notice I didn't say "professionally" because I'm not pleased with the work they did. Seaming across the roof, with Eternabond, is probably OK "structurally." But what about the edges? I'm far less concerned with the piercings, like vents, A/C, antenna... Than I'm concerned about the edges. The part I don't think I like, is taking the side edges off twice.
You'll probably learn more at the edges, about the condition of things, than around the center. I know the work is supposed to stay dry once it's all assembled and sealed. Still, I'd suggest you consider stainless steel screws.
You are Mr. Persistent. I'm sure that what you decide to do, either way, will get done. Methodically, Carefully, Effectively.