Some of the links on this forum allow SMF, at no cost to you, to earn a small commission when you click through and make a purchase. Let me know if you have any questions about this.
Have you tried a needle valve to control the gas flow to the burner ??? I use a dimmer switch on my electric element to control the temp....
You will probably have to find a burner that on "high", holds the smoker at near max. temp. you are looking for... Then it will fully adjust to the lower temps.....
AND, you will have to install a "flame out" detector to turn off the gas when the flame goes out, or you could have a neighborhood leveling bomb.....