Ask and ye shall receive my friends.
At first, I was using a couple of pavers wrapped in foil as shown below. Notice the foil pans to catch drippy things. I hate to have to scour & scrub my kettle, so these days neatness counts.
I have since been told this is a big no-no, since basic concrete/portland cement can contain moisture & this could cause the bricks to crack or worse, explode. Now, I use a couple of fire bricks bought from Ace Hardware for around $12/6 bricks. These are longer and taller than standard bricks, and most folks use them to line wood stoves. They are made for extremely high temps, so I have no worries about anything bad happening.
After some digging, I cannot find pics of the setup with fire bricks. Guess I will have to cook something this weekend to show the setup. Oh well. I am glad to take one for the team when necessary!
What I like to do is cover 3/4 of the charcoal grate with heavy duty foil. This promotes good airflow up to the coals and helps keep the mess down. Then, I put in the fire bricks, about 4" from one side of the grill. I add charcoal (usually K Blue) inside the fire bricks up to about 3" from one end. This gives room for 10-20 lit coals for a Minion method start. Depending on the cook temp, you can get anywhere from 4-8 hrs. burn time, and my kettles maintain temps from 250-300° fairly well. All you have to do is adjust the bottom intake vent about halfway open and leave the top vent wide open unless temps creep up too high.
The real trick is to get your temp fairly stable and close to where you want it before you put on whatever you are cooking. Kettles seem to maintain temps much better if you aren't chasing the temp up & down, and especially if you can catch the temp on the way up and keep it within a certain range for the entire cook.
Another method that I have used recently I call the "ring of fire". Just to be clever, I may end up calling this Johnny Cash for obvious reasons. Here's a pic of that setup:
I used more hickory in this cook than usual because these were smallish pieces that didn't burn very long.
I put a half pan under this butt to catch the drips, again avoiding greasy gunk in the bottom of the grill. I have seen grills flare up when you cook over high heat after letting grease build up in the bottom of the grill, and I guess I am attached to my eyebrows, so I don't want to have that happen. Also, a little work on the front end will save you cleanup on the back end and will have your grill ready for the next cook in no time.
Ironically, this setup with K Blue briquettes had a hard time staying @ 250°, believe it or not. Next time I use this setup, I will put a row of three briquettes on the bottom and two on top instead of two and one.
I can watch the basic temps with an inexpensive Taylor candy thermometer, around $9-10 at most stores. No, this isn't as precise as some more expensive thermometers out there, but I have learned to cook more by feel than temp, and I use this thermometer purely to make sure that things don't get out of hand temp wise rather than trying to maintain an exact temp. A Boston butt isn't very picky about the cook temp and that's mostly what I cook low & slow on my kettle. I usually try to stay around 250-275°, and most 8 lb. butts will go anywhere from 8-12 hrs. Like they say, "it's done when it's done." I will foil butts in two layers of HD foil and put them back on the grill to speed up the process a little. Here's my thermometer in action. I bent the clip that comes with it so it will stay fairly snug in the vent hole.
I promise to get some good pics that I will add to this post over the weekend. Feel free to ask questions and hopefully I can help.