I did 2 spatchcock chickens in the WSM last weekend. Exterior temp was 50 degrees, a bit windy. With all my vents open all the way, I couldnt hit 275 at the top rack. I need a simple method for insulating the WSM now that our weather has turned. Is the welding blancket the way to go? If so, any suggestions via Amazon? How do you hold the blanket to the WSM (tie down straps?)??