I'm 200lbs. I switched to a 400 coil. It's good but I think I'll be going to switch to the 450. It all depends on how aggressive you ride too. If you're bottoming out a lot then go heavier.
Good point on riding style. I'm an older guy, and still fairly new to dh, probably nowhere near as aggressive as I'd like to think... Definitely needed more than the stock though.