Another completely separate factor/possibility...if this is new construction and wood stick framing...and your trusses run front to back...you can just specify a scissor or cathederal truss instead of standard design.
I did this in my house under construction in one bay.
I'd go higher if at all possible, but keep in mind you only need that max height where the lifted car roof is. If your lift is 4 feet away from the door it might only be an issue for the first few feet of the vehicle where the hood (or deck lid, or truck bed) is.
Many missed or are ignoring this part. Adding the second floor adds significant complexity and cost. The stairs take space away from the garage, the roofline probably gets much more complicated. Trusses are completely different. Exterior wall area doubles.
Are exterior materials to match...
That's what I'd do...well I don't ever go to Dollar Stores but I buy the sheets of individual letters and numbers on Amazon and label metal tool cases and such. I mean, just seeing 2, 1.5, 1, 0.5....I think I'd know it's tons and not kilograms.
Any Generac or similar unit made for residential automatic stand-by generator runs a few minutes weekly all by itself. If there are any diagnostic issues during the run or maintenance due it can let you know by wi-fi phone app. This has been how most stand by residential units have operated...
Just get a 20-25k Generac and a single shed module for the A/C. Most likely it won't ever even need to shed off the A/C. It will be modern, reliable and have a warranty. The guys who supply it and install it will understand it and have no problem maintaining it if you are unable...or...
Given that the driveway is in the ultimate drafty, wet, and uninsulated space...outdoors...I wouldn't assume one is harder than the other without doing the math.
I think the inside could be wrapped up by end of February but if the exterior and driveway have to wait until March to restart it could be mid April. I'm not in a hurry really. I don't plan to get serious about selling my current house until late May or early June.
Not much going on in the garages...they've basically become a staging area for cabinets, flooring, trim boards, etc. The cold weather has stalled the exterior finish work, but we did get one corner done a few weeks ago and the retaining wall around the driveway apron is almost done. About...