Well Im a TOTAL noob. I got a 168cm Rome Flag and Im 6'4 220lbs and size 13 boot. All I can say is that I LOVVVEEEE the board. I got so many compliments and the feel of it is insane. I rented the first time and bought gear for the second. No regrets.
I don't know if it was the gear or what, but the first time (rental) I couldn't ride for more than 10 feet without falling. The second time I went with MY stuff, I was zipping down all the greens without bailing once.
Its pretty stiff* on the general but I feel like its perfect for my weight. When I want it to move, it moves. Simple as that.
I don't know man...I would say go for it. And as for your debate. I think some people will say 163 but my vote is for 168. I have the 168 and really couldnt imagine getting a shorter board for freeriding. Its absolutly amazing. I honestly couldn't be happier with my purchase.