Big 3 upgrade guys how much wire do I need for a 2nd gen?

Also I found some tinned OFC wire in really cool colors, it's called Knukonceptz Kollosus Kandy.
The tinning will stop it from corroding.
Will 1/0 be enough for absolutely any alternator set up I choose from or should I use 2/0?
How much wire should I order?
What are the stock wire sizes? Some of it looks 4awg some looks 2awg.
Will upgrading with a big 3 help stop head light dimming? I'm also using a 50 farad capacitor the RXC50D so I hope I won't need a second battery however I'm totally willing to buy one down the road if I STILL have headlights dimming. (Nothing's hooked up yet.)

 

1/0 should be fine... Just looked up a couple big 3 kits an it was like 14ft total (2-4' and 1-6'). Put some dielectric grease on the wire end and terminals to help prevent corrosion.

What kind of battery do you have?

 

A very nice 27F and I forget which one, it is top class though.