I have the GOSM propane unit. The $100 model from Walmart. My dad has the next step up, little bigger and has the vents/dampers on the sides. I have two pieces of stainless steel here and a metalshop that I can make these dampers in no time. What is the actual purpose of them? I want to maximize my unit, should I add these to my unit?? And if so, where to locate them to maximize their purpose?? Thanks as always, TJ