This is my 8th. Time cooking on the Egg. Everything perfect so far. I just put on a 4.8 Butt on the egg. I have top and bottom air down a good bit. Scared to close more....don't want fire/heat to go out. Best I can get right noe is 285 degrees....what to do, or if I stay there how long do I cook.....until center of Butt is 180 a 190 ish?