You're a big guy, and I think you could handle it. I'm 5'11 and 180, and ride 185 BCs through the east coast trees mounted at around -3. They turn better than my 171 Salomon 1080s...you should be okay with 189, and he did say they run short.
You're in a funky position though, I can see why you made this thread...
I think the biggest thing might be if you're truly aggressive or not, because I don't really understand what you wrote up there^. If you think you're a strong enough skier to handle 189, then go for it. You're size says yest, but what about ability?
Original Thread: "If you suddenly skied off a huge fuckin cliff and you only had time to throw one last trick before you died, what would it be?"
Malcolm: "id probably just flail my self to death"
Check these out and tell me what you think!: