For a propane smoker, close off half the gas jets on the burner. This will roughly half the BTU's and you will get a lower temp. You can run a higher flame through half the jets which will give you better control to dial in the heat low.....
Thanks for your response, I haven't thought of this project for most of the summer. I have been overwhelmed with landscape projects, haven't made time to even post any of the few cook projects i've done.
My thoughts on this project are that the orifice on the smoker burner regulates the gas into the burner. If I close half the holes, which I intend to do, then for a specific valve opening the same amount of gas will be ignited and the temp will be the same. The difference is, the flames will be higher. To get a lower temp, I would have to reduce the amount of gas into the burner.
I did an experiment in early summer and at 150° I marked the dial for the valve and then turned the valve completely off. There was less than 1/8 of a turn from 150° to off, not much control.
I figure I will give this a try, maybe in late November, when the landscape projects start to fade and the rain begins. If I don't have the control I want I will then change to a smaller orifice.
This is all just mental work, so I could easily be wrong/missing something.
I do appreciate your interest in the project. I can't wait to get back at it. For now, back to the shed.