You can get good wire from your local welding supply shop. It is finely stranded, flexible, and resonably priced. Thats where I bought the 1/0 I put in the 'Burb. They usually have a few different sizes, 4 guage would be great for your setup. You can use the copper ring terminals from them too, if you want to save $, maybe if you treat them nice they will crimp them for you too. I purchased some nice battery terminal ends from the local Batteries Plus, and they crimped them for free. Good Luck