I just did my pork shoulder tonight with lump coal. I wrapped the shoulder at 4 hours, 155 degrees and pulled it off at the 7.5 hour mark at 200 degrees. I let it rest for an hour and a half and was fantastic. The temp held steady at 250 for 7.5 hours without stoking/adding more fuel. That was impressive to me. I did place a deep tuna can over the lower vent to keep the ash from suffocating the air flow. The top sides of the can was vented.
I did want to add at least one more rack to the build, but I didn't want to drive 45 minutes to the nearest town to get another rack. The local hardware store in this little po-dunk of 700 population didn't have a replacement grate I could buy. There is ample room though, even enough for three racks.
If I do this again, I will change a few things:
Yes, add at least one more rack, possibly two.
Access holes at each grate level to insert a thermometer into the meat at the corresponding level.
Handles. (couldn't find anything at the hardware store)
Extended vent adjustment handles. They are too hot to adjust after it comes to temp. (DUH)
Possibly finding a different solution for the legs to add stability.
This however, again, did a great job for an impromptu smoker without a big box store to shop at. :)
Thanks for all the comments. Any tips or criticisms welcome!