misty,
your opening post is a little imprecise and it suggests you are looking for a simple straight-forward answer to an involved aspect of the build.
Suggest you have a search around the Internet there are many resources to help you out with planning your wiring. For example, have a look here:
http://www.constructorscarclub.org.n...ringpart1.html
for a 'How to wire your car' primer. Part 5 covers wire sizes and may give you some answers.
I hope you have already had a look round our site. If so you should have come across a very good thread in the summer with a thorough wiring diagram and (possible) wire sizes, by davidmurray.
There's plenty of information out there...
Hope that helps.