Hi, I'm Joe with the Fixers Collective.
It was my first time working on iPhones. I didn't even own one at the time.
It was a good thing that the weather was cool here in NYC because, when the first person that i helped dropped an internal screw onto the plush rug, I was sweating profusely. Several of us Fixers got on our knees, noses to the rug. It looked like we were grazing. It sounds very funny now, but no one had presence of mind to take a photo at the time. Irving found the screw to everyone's relief and amazement.
It took a whole hour to do that first 5 with several back tracks: the battery connector didn't seat well at first; the case was partially open, but we (owner's boy friend and myself) were ultimately successful.
I saw the benefit of your magnetic mat and several specialized tools.
It might be useful to have the splurgers made of a slightly stronger type of plastic as they have a tendency to distort quickly in use.
Work over the table, have another person at hand to hold down the phone when prying it open and to help keep loose metal parts in place (with a tooth pick) while getting that first screw into the battery connector- at least at first. Watching your videos was indispensable.