Overnight cook

I'm planning my first overnight cook. I read some recipes that use a Brinkman pan. My WSM has a big water pan. Does the new WSM have a larger pan then the older ones? I'm cooking a pork butt and using some mulberry mixed with oak for smoke wood.
Any additional instructions will be appreciated.

The 09 and newer have the larger water pan, see this link for instructions:

http://www.virtualweberbullet.com/pork4.html

Good luck!