Thanks everyone. Here's an update.
I got all the hardware installed. Three vents at the bottom (2 by 3/4" pipe nipples and one pipe with an elbow up to a 3/4" ball valve.) I had a pretty good thermo from a previous failed project, so I installed that.
The things I am pretty pleased with are handles and charcoal basket parts from a portable gas grill I found at Goodwill ($10 and I get handles, an ash catcher by using the lid, and a charcoal grate for the basket so I can still use the Weber Kettle)
I loaded up a medium sized basket I have for my offset with a mix of Royal lump and some mequite lump from Smart and Final and put it on a test burn tonight. It is holding temps like a champ...right between 225 to 240.
I also ran the biscuit test to check for hot and cold spots. There was a slight hot spot in the very center, but everything cooked pretty evenly. (And dang! mesquite baked biscuits taste yummy!)
I will get some pics this weekend. It is hard to get pics by the porch light after dark.