egg/weed burner question

I bought a weed burner saturday and used it for the first time that night to make some superbowl butts. Everything was going great, put the 2 butts on at 8 on the LBGE and set the stoker to 235. I went to the movies and come home at 11 and the temp was at 300, after a few adjustments I was back in business. Checked it again at 3am before going to sleep and we were still holding strong at 235 and butts around 165. Got up at 8am heard the fan buzzing away and saw the egg temp was only at 115 and butts were in the 150's. Ended up just tossing them in the oven to finish, definitly not the best tasting butts I've had:icon_frow. I removed the drip pan and place setter from the egg and found the problem..no lump left. I didn't change anything, had the lump(BGE) to the top of the fire ring. The only thing I can think is maybe I started up too much with the weed burner. I had a big pile right in the middle going. whats the best method when using the weed burner? lighting right in the middle, off to the side, a few coals lit?