I smoked three racks of baby back ribs last night. I thought they came out really good but I did run into some problems. My temp on my digi q was so different then the temperature on the lid. I ended up moving the pit clamp a couple of times and then the temperature reading came down. Is their a specific spot on the grate you are supposed to clamp that onto? I also noticed a big discrepancy when I foiled the ribs and placed them back. Could it have been because I have the 18.5 their wasn't that much circulation so the heat never really reached the lid thermometer? The bottom of the ribs were burnt, what would cause that?