I just want to add, that although I won't run the insert without the gasket, never needed to, but there are secondary burn holes all long the back of the baffle under the bottom rail that is on the baffle bottom at back. So there is going to be secondary burning going on back there regardless if the gasket seals great or not. This can be seen as a fan of secondaries coming out the bottom of the baffle at back and fanning out almost horizontally from back towards the front. Not a huge jet stream, but like I said, a fan of secondaries, in mine it is usually a few inches long. I know I saw the secondary holes back there under that channel pc. Tough to see, but at the right angle with the baffle out, I def saw them.