I understand for lighting on aftermarket gauges (Temp, air/fuel) that I can tap into the radio dimmer wire for power.
The question is, can the dimmer wire be used with more than one gauge? (Can I splice both gauges into the same wire?)
You should be able to use the same dimmer wire connection for multiple gauges. Be sure to have a good ground for each gauge. Solder the wire connections & cover the solder joints with heat shrink tubing.