I tried the Herb Crusted Prime Rib recipe as our first WSM BBQ on Saturday. Turned out well but had to cook for a lot longer to get the meat to the right temperature. The recipe says to use Kingsford charcoal but we only had Weber Briquettes. The temperature initially went up over 370F but quickly settled back to c270F. The recipe says to keep the temperature around 360f for the entire cooking period but we averaged around 270F with all vents fully open. We could get the temp higher for short periods by adding some old unused cedar wood tiles. Would the temperature problem just be down to different coals or are we doing something else wrong?