I've been accumulating materials for this project, and now that it's November, I'm out of the end-of-month rush for Hackaday writing and can actually devote a few cycles to this build. 

The time-consuming part will be the metalwork for the scale bases, so I thought I'd concentrate on prototyping the electronics and building the code first, mainly because my garage is a mess and I can do the other stuff in my office.

The basic components will be:

1. Two 50-kg load cells
2. Two HX711 load cell amps
3. A Wemos D1 mini

Each scale will have a load cell and an HX711 board -- I want to keep the connection between the load cell and amp as short as possible. Each scale will be wired into a junction box mounted on the outside wall of my shop. I'm debating whether I should put the Wemos inside or outside -- probably inside. The only reason I can think of to mount it outside is to add a DHT11 shield for outdoor temperature measurements. But that means the outdoor junction box would have to be vented, and I think I'd rather have that waterproof.