2x2 Twill weave is used for visual carbon parts , the bigger the K size such as 3k , 6k, 12k, is basically the size of the print or how big the bundles of carbon strands are. 3K being small around 1/16" 12K being around 3/16". As for weight of fabric 5.7 ounce is very conformable and you should not have a problem all the way up to 10-11 ounce. Just be aware that if you want a very nice cosmetic look , one layer of carbon tends to show the underlying surface through between the strands, you are better off with 2 layers of 5.7 first on 0 and 90 deg , second on 45 and 45 deg. Dont expect 2 layers of 5.7 to make a huge difference if you are looking for reinforcing strength along with the looks. If you spending the money my suggestion would be 2 layers of around 10 oz 2x2 twill, 0/90 and 45/45. This will give you the look you want and strength for your money spent.
