First of all... AWESOME GRAB for 25 Buckeroos!!! I have the same WSM.
I keep 2 of the 3 bottom vents closed. The third vent I crack open to 1/2. I keep the Top Vent wide open. I use the Minion method and have had great results! I also rely on my Maverick to monitor temps. Once she settles in around 225 - 250, game on... She will run steady at those temps for HOURS!!! Last cook was 2 Packers and it held 225 for almost 13 hours. By then, Beef was done. My first go with the WSM was with Stubbs. I wasn't prepared for the run away temps. I normally use KBB. She hit 325 before I shut down the top vent and bottom vents to get the temps down. Took about 40 minutes to settle her down.
For the 2nd cook, I had some ceramic Briqs. (From a gasser project years ago) I foiled the water pan, dropped in the Briqs and foiled over that. Seemed to keep things calm for the entire cook. Some swear by water in the pan, and some don't. No Water = easy clean up...
YMMV
Good luck and awesome score!!
As far as the door goes... I just deal with it. I am afraid to pull the trigger on the Cajun bandit door. Trying to keep $$$ in the kitty for meat.
Jeff