long burns

i have a typical 55gal UDS with a 13inx12in round coal basket. round metal grate on the bottom and expando on the sides, elevated 3-4inches. 3-1in inlets and 2in bung on a flat top lid. i burn lump, RO or Malic's, with hardwood chunks. I typically fill the basket about 1/2 way with lump and...