Dimming Autometer C2 Gauges

I'm not much of a night person, so I don't do much driving after dark. But after switching to Mid-Shift, I quickly noticed something about my gauges.  Autometer's bright blue LED backlights on their C2 model gauges are blinding at night! And having 5 of them installed just makes it 5x the problem!  I need some help picking the right rheostat/potentiometer to dim these babies down!  I have them all running off one 12volt  illumination switched wire, so installation should be easy once I know what will work.  You'd be surprised how ignorant the local RadioShack employees are of their own job, even the ones who seem to have chosen to go career... *cough*  Please let me know what will work to dim these beacons of light which as you can see glare right in my face. Thanks in advance.