You also have to consider if you go bigger that you'll probably need to change the gearing in your rear end. If you don't, you'll end up tearing it up if you go hard.
First things first, if you don't have a cab mount cut, don't matter how much you cut the fender or the flare, it's gonna hit the frame work of the cab support bracket. There's different company's that make CMC plates so do your research and go with what you want. I'm attaching pics of mine.