I have asked this question before but as part of another post and I think it got buried. I am installing a quadra-fire 4300 in my basement attaching to metalbest stovepipe. The allowable clearance from the top to combustibles is 53 inches. The allowed clearance from the rear to combustibles is 11 inches with single wall pipe. I am concerned that even with these clearances the distance from the top of the stove to wall is less than the 53". Am I being overly cautious when I think I should shield the back wall too? Is the 53 inch measurement really meant to be taken at a 90 degree angle to the stove top?