I have cooked all my lo and slo on my wsm.
I use the kettle (OTG) and cook indirect using the charcoal baskets, 9 X 13 pan with water in the middle. Temp will quickly jump to 400*. Only open the bottom vents about 1st knotch, top vent open. How do you control lo and slo?
MM or just vent control? I use about 2/3 chimney of lit coals to start, fill each basket.
Cooked some country style ribs yesterday. About 45 minutes and they were 180

See here.

the reffered site is a good referance. i usually use my bar b que version(three lower vents) so its kinda easy to just shut two off and control with the one. i stack up my coals on one side over the one open vent. as you have a one touch this is what i did with mine. with the thought of putting the coals on one side i cover the lower charcoal grate with foil except for the area were the coals will go. i also hang foil from the upper grate to the lower grate just an inch or so from were the coals will go. kinda like a barrier. drip pan under the meat and yer ready to go. control the temps with the lower vents. as i usually leave the upper vent open. some folks mark the lever for opening referance but i use a large mirror. this also helps me to see if ash is covering the openings. a few minutes with the foil and yer good to go. easy.

Here's a couple of pics using foil:



I used a ball of foil to hold the grate open and foiled the raised grate too. The side of the coal basket is also foiled.

I wouldn't recommend Cowboy lump for anything anymore. I burned through so much of it on this cook it was stupid.

I regulated the temp primarily with the top vent only, leaving the bottom ones closed. I thought it was a lot of work and can't wait for my WSM to arrive.

I find that using hardwood briquettes instead of lump makes a big difference. Get the coals burning, lower vent pretty much closed, top vent wide open unless it gets too hot, and I can get ~3 hours or more on a single basket of coals. I find lump burns too fast and is much more likely to go out when cooking low and slow.

Also remember that the "grill to top of lid" temperature difference tends to be higher in a kettle than a WSM, ie 300 at the lid is about 225 at the grill.

I used to use a water pan but don't bother these days unless going for an overnight cook with a big pile of coals and Minion method.

I started smoking on a Kettle. It does do a decent job, but you do have to be very observant of the cooking process. Tomorrow I am doing 3 full cap briskets. I will do 2 on my WSM and 1 on the Kettle. For smoking on the Kettle you use the top vent to control the heat
I use Kingsford and chunk hickory for the smoke. The only problem is that as soon as I serve it the brisket is gone-what happened?