The first job was to get the heater and gas supply installed. Aside from cutting 9" diameter holes in the interior and exterior walls of my shack without hitting any studs, this went smoothly. Running the gas line was not quite so smooth -- many trips back in forth to Lowe's and any plumbing supply store I thought might have 3/8" black iron pipe. Pro-tip: use the much easier to find 1/2" pipe and neck it down with reducers or bushings.
Not a bad looking job if I do say so:
I would have been a bit more comfortable getting the tanks a little further away from the heater exhaust, but it's OK the way it is. And before anyone starts with "that's not code!", I know. But this is North Idaho. It's OK.
The regulator between the two tanks is a switchover regulator. One one tank goes empty, I can switch to the other tank and run off that until I get a chance to get the first tank refilled. I suppose switchover could be automated too, but that's probably overkill.
When this is done, the tanks will sit up on separate scale platforms. Each scale will have a load cell and amplifier and be wired into a box with a Wemos D1 Mini. I haven't decided if I want the Wemos inside the shack or outside yet. Probably inside.