Kelly, the burner I'm using is the 180k btu burner that came packaged with the Brinkman barrel smoker. It's the same one I was using in my MBE. You can see a picture of it in that thread.
I can double check on the specs later but I believe it is a full half turn on the inline regulator knob to full open and I believe I open it up 3/4 of the way to full open when heating up. Hearth temps taken right in the middle of the stone is about 650f within an average of 18m or so of heating up. If I don't open up the inline regulator as much, it takes longer to reach 650f. I'm also using the 18" weber, so your 22" kettle may take a bit longer to heat up, I'm not sure.
After I bake the first pie, I typically turn the burner regulator knob down a bit, while I take the pie in for pictures and a taste test. By the time I open up the 2nd skin and ready to bake, the temps are where I need it. I typically bake about 30f lower on the 2nd and successive pies. I can dial the temp of the hearth in by setting the regulator knob accordingly.
The propane valve on the bottle is open all the way during the entire cook session.
To cure the white rim, you'll likely need to open up the lid vent a bit more. What size is your lid vent? I can measure mine later today. When is the opening sufficient? Your LBE should sound kind of like a jet engine. When you open up the lid vent a bit more, it should sound a bit louder, like the LBE can breathe better. I can make a video showing the setup and how it sounds or even me baking a pie if you want. After that, if you are still having trouble with the rim, I would recommend installing a lid air deflector as seen in my pics.
UPDATE - I just check my inline regulator knob, and you are correct PB. It turns a complete 2.5 times before stopping. I open it about 1/4 of a turn or a bit more, but quite a half turn when heating up the LBE.