upgrade to factory rallye gage backlighting

Finished up my ammeter to volt gage conversion. All thats left is to clip off the needle on the volt gage and use the original ammeter gage pointer on the volt gage so everythings a perfect match, and tweak the pot to get the needle to read where i want it at 12v.

I also installed a mini denso 50A alternator. Its plug has a spot for a fault light. I am contemplating installing a very small diameter red led next to the discharge side of the gage face. Something thats not obtrusive and easily overlooked unless its lit.

Also thought about doing this with my in dash vacuum gage with a small high bright amber 12v led hooked up to a hidden adjustable proform shift light. Same thing make it un obtrusive unless lit. Any thoughts on this? Good idea, bad idea?

Matt