I think that the double 16 gauge thing is a good idea only if you have the two cables immediately next to one another. (See this article. Yeah, yeah, same one.) However, 12 gauge should be enough. I wouldn't waste money on Monster; just get some from http://www.partsexpress.com or something. I belive there are some other threads on flat cabling 'round here.

I am the Doctor, and THIS... is my SPOON!