I use only lump in my UDS(with apple wood chunks for flavor). I have found that lump gives less ash and burns cleaner than briquettes. My fire basket is 14 inches in diameter, and 12 inches deep. I usually load it about 9-10 inches deep, and have gotten as much as 16 hours of cooking time. On the other hand, I prefer briquettes for grilling because of better temperature control on the grill. Just sayin' my .02 cents worth.
SNPP w/ mods, Patio Master(30 years old), Kettle Grill, Copper Penny UDS, and Maverick 73 thermo.
Youth and enthusiasm are easily overcome by old age and treachery.