I am working on a cinder block pit build for whole hog. I have the general layout and concept together, but my main question is about air flow. I am used to smoking where I have control of in and out. I see on most pits like I am thinking of (Meat Church and Amazing Ribs) that they don't have an exhaust. Does this type of pit not need an exhaust or does the gaps in the brick or lid provide enough air flow? I am going to try and stack things tight, but realize there will be gaps as is the nature of the beast. I was going to build an insulated lid, but try to use flat sheet metal and not corrugated so there may not be gaps in the lid to create an exhaust. Any issue with this or should I turn one of the blocks to make an exhaust?