I think the op is designing and building the enclosure for the manufacturer and not the property owner. Sounds like they want a unit that they will provide when they sell a unit for exterior installation?
I have a time tracker app that lets me clock in and out when I am on a job. Makes tracking how much time I put into a job super easy. I also take lots of pictures. When I was in construction, we used pictures for all kinds of things. Good protection if you have "before" pictures and a customer...
craigslist and then youtube. check out Donyboy73 he is a small engine mechanic and has a huge library of videos on small engine repair. I found a lawn mower in a creek near a jobsite that someone had dumped there. watching his videos I was able to diagnose bent pushrods and for $14 I had a...