Why not just use an oven
I've done it more than once over the winter when chit was freezing cold and windy. No shame in my game. Although I did setup the maverick on one of the cooks just to see how close the oven's digital readout was. Come to find out I was getting bigger temp swings in the oven than the wsm. Go figure...
WSM 22 ~ WSM 18 ~ Maverick ET-732 ~ Flaming Fast Thermapen ~ Weber SS Performer ~ Weber 22 OTS ~ Weber 22 OTS ~ Weber 22 OTPlus ~ Weber 22 OTS ~ Weber Q300
When all else fails just ask yourself, WWGALD???