GTG with either rail, IMHO. I too am not a huge fan of the FDE color but the RIS II, technically and functionally speaking is just superb.
We're about the same height. That said, stock length depends quite a bit on shooting style. While I personally like having my CTR on the first position out, practically nose to CH, I know a couple of folks my size who like theirs all the way out if not just a slot or 2 from it, as well as a few guys much larger than myslef who like theirs in the same position as mine.
Again, subjective to what works for you. You may want to try one at different positions if that's at all possible, just to see what works best for you.