If you have to wire up stuff again and you need to have a series of grounds or hot wires you might try this instead of twisting two wires ard putting them into a connector thats made for a single wire. It also gives you some more slack in the wire so you can work on it if you have to. They also make insulated female spade connectors so you can be sure nothing can short out from wires touching. You can see them on the back of the gauges.
When you put the wire into the connector try not to push it past the insulation. I hate messing with wiring so after I do the crimp I put a small piece of marine shrink tubing over the terminal end and a little over the wire so it wount ever come loose. The marine style has adhesive in it so it kinda glues itself to everything. I never want to have anything come apart. Not picking on your work. Just a suggestion trying to help.