Yeah, gray and blue seem right, all your instrument cluster lights are controlled by the potentiometer but I seem to remember reading something about that control being indirect. I haven’t checked, but there may be an integrated circuit or its' module the pot is connected to, the dash lights are provided their voltage from the IC/module in direct proportion to the adjustment of the pot. If that is in fact the arrangement then you could pull your instrument cluster and follow the wires from the cluster lighting back to their source as there are numerous lights they all should converge somewhere. At that convergence point you may find an unused extra connection or some other attachment point i. e. a solder pad or the like. If not then a parallel tap into a lead from a cluster light should have a minimal effect as the bulb that illuminates the LCD is very low power and will have a very small current draw, but to be safe if you use the parallel tap scheme pick the cluster lamp that will have least overall effect, like one to the side rather than the overhead gage lights.
Good work Ryan, just a tip, the flow of electricity is similar to the flow of a liquid. Electrons are the water and the insulated wire is the pipe. Switches are like valves. Schematics are often easier to decipher if you eliminate those portions that do not make direct connections to the components you are working on, if you can segregate a portion of the circuit it is sometimes easier to understand what’s happening or supposed to be happening.