TWQQ - Like you, I did my first smoke yesterday, and I seemed to hover around 300-350*. Here is the link to the thread on my first smoke.
I had everything closed at one time and it didn't seem to be going down in temp. It was windy and that air space between the firepan and body seemed pretty large. I'm trying to think of a way to seal up the firepan to the body, but not sure which route I want to go.
I'm going to try less lit charcoal when I do the minion method. I have to get the temps under control because I am doing some ribs for a party in 2 weeks. The thermometer I used was one that was just hanging off the rack that I picked up from Fleet Farm. I'm not sure how accurate it was, but I have a Maverick ET-732 coming in tomorrow that I think will help me run some better tests.
Good luck because it sounds like we have similar situations. If you find things that work for you, PM me, or just post to a new thread with ECB in the title. I'm always looking for those.