I'm 6'-2" and peaked out about 285lb (on my way back down luckily). Wear 2XL shirts and coats. I had the old one-size BCA vest for a couple years and it was ok adjusted out all the way, but was tight, I fought the zipper wanting to go down on it's own throughout the day, and it seemed to always want to ride up in the front (toward your neck). I tried on the most updated version BCA vest in the XL/XXL size at the dealership last fall and I broke out the credit card right away. The fit is much better for bigger guys and all of the issues I had with the old design are now gone with the newer one. I have the adjustment points let out most of the way, but there's some room to go yet.
If there's a stocking dealer near you I suggest doing what I did: go in with all your upper body gear (coat, helmet, and in my case neck brace) and try the system on like that. Cinch it up snug, but not too tight, and jump around. If it fits and doesn't move around on you then that's the one to get.