I also agree with
@jjrandorin and
@SMAlset's comments. You'll have a better alignment of expectations if you recognize your role as project manager; and the people you'll be dealing with are going to be very difficult to get a hold of since they're over-worked and under staffed.
But I would add that I think Solar (and especially Powerwalls) is not like a typical home construction project. In the last 18 months, I've completed a full kitchen remodel, bath remodel, two zone HVAC replacement, and tried to get Solar + ESS.
The kitchen and bath remodel took 10 calendar days (5 planning, 5 working) and was a relative breeze. The people involved had everything lined up; the workers were great, and like zero hiccups after we spent some time pre-planning everything. The only hang-up I had was the fridge was actually taller than we had measured (due to the feet on the bottom not being as adjustable as the manufacturer claimed) and we had to cut a piece of trim.
My HVAC replacement of two condensers, two air handlers, and two evaporators took all of 2 days (1 planning, one working). The crew was amazing; the only problem I had was the contractor swapping out parts for lower-end (lower efficiency) items behind my back.
But Solar and ESS ... this industry is completely BS. For the record I went with Sunrun instead of Tesla. But I suspect the big corporates have similar issues.
The reason solar+ESS is unlike a typical construction project... is it intentionally exposes the worst possible aspect of relevant stakeholders. The only thing I can think of that is worse than this on a residential project would probably be a a full demo/rebuild. It seems like some of the parties involved actually want you to fail; and bring a burden along with it that is mind boggling.
Design is super difficult since every house is different and every jurisdiction is different. Whether it be your gutter flow rate, location of gas riser, having a shear wall, slope of roof, age of underlayment, shingle/tile type, chimney location, skylight setbacks, conduit paths, flashing density, sub panels, generation panels, undersized busbars, NEC 120% rule; above/below ground service blah blah blah. There's a rule and unique AHJ disaster just waiting to screw you up. I don't know how anybody gets anything done.
Permitting and Inspection is borderline impossible with HOAs throwing hissy fits; extra breakers/disconnects everywhere; smart/dumb meters; gaps between equipment; bonding/grounding; fire codes; ladder access; warning labels; line of sight; bollards yuck yuck yuck.
The actual work of the install seems to be the only thing that is straightforward. The people who do this work for a living are typically really good at their jobs, and will make you feel good about what is happening.
But everyone else in the process seems well versed at giving people the run-around, shrugging their shoulders, or otherwise just not responding at all because they're in a back office somewhere and seem to be overworked. Good luck trying to get government incentive paperwork or post-service help like getting your solar array map (per panel location on your roof). And if there's actually an equipment problem that's a pretty hefty delay to get back on people's radar.
I just hope your local utility grants PTO quickly as well. I think the PG&E area is up to 45 days wait for PTO due to their backlog.
