Voltage range for guage cluster bulbs?

[FyreDaug]

I got my dash apart finally and im going to do some custom gauge work, my roommate will do the designing since hes got some artistic talent. And I'm wiring up LED's in it. So right now, the problem im having is I dont know what voltage go to the 4(?) bulbs in the guage cluster. Like when the combination switch has the setting on dimmest, how many volts, and when its on highest how many volts?

Is it safe to assume the BRIGHTEST will be 12V? (or 14.4ish)

[POS carb]

I used ~500 ohm resistors per LED to get desired light output, also the dimmer adds additional resistance when dimmed (the LEDs will dim with the gauge lights) Don't mess with the gauge wiring, just tap the 12v to each LED/Resistor combo
I do not recall the resistance of the dimmer circuit.

[FyreDaug]

how bright was 500ohm and how many LED did you use? I actually plan to use quite alot of LED's, in a cool way and have some of them dimmer than others. With that 500ohm how close to max power were those LED's? I dont wanna push em too hard and have to do all this shit again. This is a 1 time thing hopefully. Was each LED wired in parallel? (Not 1 LED connected to another pos to neg... ie series)