LOL this is great! As for the Depo gauges, a couple of them were purchased from a vendor who had them laying around. The 3rd was purchased off Ebay. They look like Defi knock offs, but hopefully it gets the job done. The motor is the stepper type. There is no need for a central module for these gauges. It is possible to daisy chain the power connections. Each come with a small touch sensor that can be mounted remotely, and it can be used to change the backlight color and set the alarm threshold.
DEPO
If I knew earlier, I would've gone for the 4-in-1 gauge. It's an analog gauge with an OLED display for 2-3 other sensors like voltage, water temp, etc.