Instrument cluster fixes/upgrades?

70 Duster, rallye dash. I was having some lighting issues so pulled the instrument cluster out. I believe I had some bad grounds, cleaned them up and tested using a 12v motorcycle battery and it appears they are now good. But while it is out, I am going to inspect and upgrade some things so I hopefully never have to pull it out again. Once thing is upgrading the IVR from mechanical to solid state. Think that is a should do since it’s out.

I am really on the fence about converting the ammeter to voltmeter. I have done Crackbacks headlight relay kit and also his Alt-batt cable. I have disassembled and cleaned the bulkhead connection and feel that is pretty solid. I do have efi, the display shows volts at the battery so I do monitor them. The benefit I see by getting rid of the ammeter is eliminating all the power going through it, if it malfunctions things shut down. But with Crackbacks upgrades is that something I still should be worried about? On 50yr old wiring? Did I just answer my own question??

I will be sitting down today going over the wiring diagram to find a key on 12v source if I go voltmeter. I do have a wire for an electric choke being unused I could thread through, can’t remember exactly what it comes off of but would that work? I believe that is key on only. How many amps does a voltmeter draw? I would think minimal.

Since I got this cluster out, is there any thing else I should inspect? Right now only other real issue is the trip odometer hangs up, so speedometer will be opened up probably.