Wire size?

[thanson@frost.com]

     I want to run a wire from the coil up to the dash to power a 
     tachometer. What gauge of wire should I use? It is a six volt car, so 
     I believe the wire will need to be "thicker" (a heavier gauge) than 
     the wire one would uses in a twelve volt car. 
     
     Where should I run the wire? Where can I pass the wire from the engine 
     compartment to the inside of the car? Once inside the car, can I run 
     it near the voltage regular, then under the carpet?
     
     Thanks in advance for any suggestions.
     
     thanson@frost.com