This is a particularly interesting thread because I am entertaining the thought of constructing a basic manual sample roaster with a solid barrel; thanks for such a thorough review of the Huky. Thinking through some of the phenomena regarding ET and MET vs airflow with your particular setup I am wondering if the unpredictable results are a result of the heat exchange from the gas burner?

I.e. to me it seems that your burner is producing excess heat that escapes around the outside of the roaster. When you increase the exhaust flow you could be redirecting the excess heat into the roast instead. Although I can't exactly say since I don't have a gas powered Huky.

I was also wondering if you find yourself utilizing the full power of your Bluestar or whichever other burner you are using? Since I am preferring an electric roaster design with a similar bean capacity I am trying to understand the power requirements.

Edit: I am totally inexperienced in roasting btw but I have somewhat of a sick affinity to costly diy projects; i've recently convinced myself that a diy roaster will add more value to my coffee experience than an upgraded espresso machine.