Flexwatt Wiring Help

So I bough 6ft of 4inch Flexwatt and I need some help figuring out what gauge wire to use. The instructions just confuse me lol. Anyways, I'm going to be doing (6) 1ft pieces of 4inch Flexwatt (8 watts/ft) and I wanted to wire them parallel. I read that most people use extension cords but instead of buying extension cords, I can get any gauge wire from work. So I'm asking the pros, what gauge wire should I use?

I use Extension cords and buy bulk extension cord wire at Home Depot works great for me and is not to expensive .40c or so a foot

Ok, I ordered a cord from Bean Farm and it says it's 18 gauge so i'm assuming 18 gauge will be okay. Can someone confirm this?