Is a "facecord piece" 48" long? The barrels are 34" high. I have put 6 or 8 pieces of very large broken fence post that long into my lower barrel (with a foot or so sticking up into the chimney barrel) surrounded by smaller pieces of very dry wood. I placed crumpled paper balls all over the top of the big pieces, and then installed the top chimney barrel, with two three foot pieces of rebar separating the two barrels. I ignite the paper, and start throwing small pieces of "kindling" on top, and later, some brands from a previous burn. The idea is to get a good bed of coals on top, sucking air up from the bottom of the lower barrel, and burning down toward those air holes. Usually after 60 to 75 minutes, the air inlet holes start to show glowing char. Cover those glowing holes, and start the sealing process. If you poke around in the barrel (I used a crooked steel T-post), you will find that the large posts are mostly gone, and you will be able to install a flat lid. The whole idea is to bake this wood and drive off all the water, gas, tar, etc. Insulate the barrel if possible, so as to extend the baking process for those facecord sized pieces which are now much smaller. The lid must be air-tight, and don't skimp on the dirt covering the holes. Go about a foot high with the dirt. Twenty four hours later, at the earliest, you can dump it out. Those big posts will be little hunks of charcoal! If not, set up the barrel again, put the unfinished pieces back in the barrel, add new wood, and go again. Watch the stuff you just dumped out, to be sure it does not ignite. You won't see any flames...it just turns white and will melt your shoes. If you don't need the charcoal right away, I see no problem with putting two or three buckets of water on top of the pile to make sure it doesn't start up, plus it washes the ashes and fines down to the bottom. My very best charcoal is made in a completely sealed 20# propane tank retort, with only four 1/4" holes for gas outlet. The charcoal is totally black, has no ash, and rings like a bell. The attached photo shows an overloaded barrel of very dry junk wood just before I installed the chimney barrel. There were some four and six inch diameter wood chunks in this load, but they were bone dry. It made good charcoal. My usual run is 60 to 75 minutes. If you go longer, it burns up your charcoal! Shorter, and you get a bunch of "not done" brands. The idea is to BAKE, not BURN. The only smoke during the whole process will be a bit that blows out when the lid is first installed. You can minimize that by waiting 15 min. or so before installing the lid, as long as there are flames consuming any gas.