First I want to thank everyone who chimed in, you have all been so helpful!
I especially appreciate pointing me to 'VDO'. I thought I was missing some terminology because my google searches were all bringing up the wrong kind of gauges (ones with probes already attached). The VDO gauges so far look to have detachable sending units and seem to be a better fit both aesthetically and electrically.
For the VDO gauge in the image above, how should I connect the Red-White-Black wires?