Introduction to X-Carve

I’m getting ready to pull the trigger on the X-Carve and have a question? I have a Bosch Colt, so I was going to sans the spindle and power supply in the kit. My question is - what would be an adequate power supply to power the stepper motors? I know the cooling fan in the kit is rated at 24 volts, but I have plenty of 12 volt fans laying around. Could I get away with a 12 volt power supply or should I play it safe with a 24 volt 150 watt power supply? I’m just going to throw a bone here, because I know ultimately it depends on many factors but…The main reason I’m purchasing this is to mill small wood project boxes out of 1" thick hardwoods. I’m more concerned with accuracy than milling time, would I be better off with the included quite spindle?

Thanks