change in gas and temp gauges

Are we to assume you're talkin about the car in your avatar?
Yep, that's the car - 70 Dart standard cluster - not rallye dash

You need to treat troubleshooting cluster/ gauges like an end to end system
yeah, I hear you, but before I go through the special hell of pulling the cluster to do that, I'm trying to figure out if it's worth snaking my arm up there and replacing the voltage limiter. Since the only things acting up are the 2 gauges that are attached to it and they both went wonky at the same time...