I have a
Masterbuilt propane Smoker and was having the same issues with the inability to hold Temps below 250.
I made skirts out of cement board (painted black with high temperature spray paint) and placed them against the legs of the smoker. I followed the same angle as the legs. This has helped with wind blowout of the flame at a low level. The other thing I did was add a needle valve.
This has allowed me to dial in the temp with much more accuracy than the stock control valve.
I used high temperature foil tape to block some of the vent holes coming into the chamber.
These three mods have allowed me to hold Temps below 200.
It's night-time here but will post some pics this weekend.
r2