I keep wondering the reason behind folks wanting to maintain the 350-400 degree temps using a WSM? For high heat (like that) I don't understand the reason to use the WSM, those are basic kettle temperatures. What are the proteins being cooked in that manner?
That is not heat used for long cook times as far as I know, Minion method is designed for fuel conservation which those temperatures will not support.
If you are doing something like fulll power high temp work, take the pan OUT (no reason for the heat shield and, even less cleanup), the distance from the live fire is far enough that, unless your birds sweat gasoline, flares should be minimal.
Also, take the lower cook rack out too unless you have a deep seated fondness for cleaning racks.
If I'm missing something about all this please feel free to enlighten me but, high heat means large quantities of fuel, burning pretty much full on not really one of the things I have ever thought the WSM was designed for not saying it's impossible just not what it was designed for.