Jegs Gauges

Chi Com. I have had such good luck with Autometer over the years that I stick with a known commodity. I also prefer mechanical gauges as they tend to be more accurate.
I use -4 for the oil pressure gauge as the larger dia. line lets the gauge react quicker.
water temp is easy to test with a pan of boiling water and a thermometer. Volt meter is electric , obviously , but they are good parts for a little more $$.