volt gauge or not?

My comment is nothing more than that...a comment. In no way would I attempt to change anyone's mind about the discussed mod.

Ammeters were the only electrical system monitoring device for decades and were used on tens of millions of cars and trucks without problems. Yes, sometimes charge monitoring circuits fail catastrophically, but usually because the owner did something wrong with the wiring, and was not the failure of the ammeter.

Just as ammeters don't tell you your battery voltage, voltmeters don't tell you if your charging circuit is operating. However, when you are familiar with an ammeter, it tells you much more than the fact that the system is charging.

I'll leave it at that, but given the choice I would much rather have a properly functioning ammeter than a voltmeter.