first overnight smoke question

I have a new WSM 22in that I have used twice. Tomorrow night, I will be doing 2 butts. I have read a lot on this board about the clay saucer and how much less fuel it uses than using a water pan. Is this true? If I use the water pan and start the smoker at 9pm, when would the water run out? If I use the clay saucer, what size would I need to buy for the 22in? Does the saucer help the smoker use less charcaol? If so, would I be able to smoke for 9-10 hours on one big load of minion method charcoal? Also, I always use lump, can I get 9-10 hours off of a minion method of lump? Any help would be greatly appreciated. I used an offset for a couple years and got really tired of waking up every 2 hours to load the cooker, and would like to know the best way to use the WSM to cook overnight.

I am doing my first smoke on my 22 WSM also. I have this thing stacked with lump using the minion method. I too am used to using an offset and going out every hour or less to tap on the dampers and feed the monster. Im at 228 right now and I hope it stays. Its been an hour or so. I just want to reload it already just because. Good luck on your cook.

J, I wouldn't worry about the saucer. I've been using an empty water pan covered with aluminum foil for years and everything comes out great whether I do the high heat or low and slow. If it's really cold when you start I'd use a bit more lit on my lump initially. You'll need that extra boost. Post pics and have fun

Another vote for the double foiled empty water pan. One layer of foil on the bottom and another layer closer to the lip of the bowl, leaving an air gap in between. Top layer catches the drippings. Replace the top layer between cooks (if desired ;-) No need for water in the smoker.

Got the 2009 18 WSM almost a year ago, and used the clay saucer in it for the first few cooks. Then read something here and the light went on. Never looked back.

Differing from quite a few people on the site, I do use water in my pan. However, once it's gone, I don't refill it. I've found that with my WSM, the hardest time I have maintaining my desired temps (anywhere between 225 and 300 for me) is at the beginning, so I use water as a heat sink for that time. When it all boils off, I don't refill it. It actually helps out because near the end there's little or no water in the pan, so the smaller amount of charcoal in the cooker can help hold the temp I'm looking for.

Now I don't have a 22", so it might be that your water pan will last the whole time if you fill it all the way up, since the 22" have a bigger waterpan than the 18" IIRC. I also place a layer of aluminum foil over the pan after I have placed the initial water into it. Not only does this discourage the temptation to refill the pan, it makes cleanup much, much easier, and I can't recommend it highly enough.

I also second Paul's comment about using a bit more lump initially if it's really cold out.

I'm a convert from water in the pan. I now use only a foiled pan with a foiled brick. Any size clay saucer will work too. Yes, you will definitely save on fuel, especially in the winter. I smoke with K comp, but others use lump with good results. Pack that lump in tight. You can't use too much of it. You can always reuse what's left over next time if you close all vents as soon as meat is finished.
Good luck and post pics when finished!
For lump vs. briquette conversation, see here.