Depends on what I'm smoking. If it chicken or something I want at a high heat I may load two full charcoal chimney's of lit coals. If it ribs or something I want to smoke a a lower temp, I put unlit on the bottom with a few chunks of wood for smoke in the middle and lit coals on top. My opinion is the lit coals on top will help burn any acrid smoke produced by the unlit below as it lights. I do give the WSM time to settle down and usually any fresh acrid smoke is long gone before I put the meat in. Depending on how long a smoke I'm anticipating dictates how much unlit I put on the bottom.
For an overnight smoke of pork butts, I load the fire ring nearly to the rim, put in 3 chunks of smoke wood, and top it with a single even layer of lit. My standard smoke for 4 pork butts (I have the 18.5" WSM) is get the meat on the smoker between noon and 2PM. Around midnight I will check the pit. I usually pull the body of the WSM off (lid still on to retain as much heat as possible), grab the fire ring with welding gloves to give it a good shake to drop the ash below the grate, then use tools to push the remaining lit to one side in a cluster with one edge in front of the GURU inlet. Then dump in more unlit and put the body back on. Temp will spike by about 10-20* within a half hour, but settle down for the rest of the night. Whole process takes 2 minutes tops. After I'm satisfied the spike is settling down, I'm off to bed and sleep well. Depending on the stall, meat is done between 6:30am and 8:30am (and also depending on exactly when I got it on the smoker, more often than not it's on the 2PM side of the range). I run shoulders at 225* and never have to touch anything from loading the meat until topping off the smoker. I run a clay pot base and have run the entire smoke on a single supper stuffed load of charcoal, but charcoal is cheap and the midnight top off gives me peace of mind there is plenty of fuel for the pit to run on until the end.
Some people use modified minion methods. Some make a ring of charcoal around the outside edge of the fire ring and put the lit on one end. Some people use a can in the middle or just leave an empty hole in the middle surrounded by unlit and then dump in a small amount of lit in the can or hole.
They all work, but for me, it's lit on top of unlit (just a single layer of lit is all it takes). Once the WSM is stable on a BBQ GURU or other power draft, it should remain stable as long as their is fuel to burn.