So, I'm sure there is something posted somewhere on here but I can't find it. I have a Weber Smokey Mountain 18.5". I want to put some lining on the door to reduce the air flow in from the door during cooking. Does it matter if I put it on the door or the smoker? Thoughts? Also, I need to close off 2 of the 3 vents on the bottom, I use a BBQ Guru and I am having problems restricting the air flow, is there a good way of easily closing them off? Thanks!!!