I use my 22" Weber with a coal baffle and lay packets of chunk apple wrapped in heavy foil on the coals under it and smoke cook my brisket. This brisket sat on the grill on a sheet of heavy foil with drain holes poked in it. The large end of the brisket was on the coal end of the kettle. I start the first coals [about twenty of them] on one edge of the coal grill. When they're mostly gray I put the two smoke bombs, as I call them, on the coals, put the baffle in place and cover the grill after setting the top grill and meat on it. At about two hours the smoke dwindling will tell me when I need to take the top grill and meat off, pull the baffle back and add ten or so briquettes to the hot coals and put the next two bombs on the coal bed, then the baffle and replace the top grill/meat. About 2 1/2 hours after that exchange I repeat it. When the smoke dwindles after the third coal and bomb load I'll slip a digital fast read thermometer in the thick end of the meat. If I get a reading for medium rare, its done. Doing the meat in this fashion will render medium meat on the thin end of the brisket clear up until it starts to get into the 3 1/2" to 4" range, from there forward its pretty much medium rare. The brisket is pulled from the grill at that point, wrapped in heavy foil and allowed to rest until I can handle it with my hands and not get too warm, then I remover the foil and slide it in the fridge until fully cold, then put the foil back on until I take it out to slice it. I slice it by hand somewhere between into 1/16" and 1/8" thick slices.
I looked in my smoking journal this morning journal and this is my 37th brisket in about 22 years. No rubs, no marinades, no salt, just meat and smoke. I season it the way I feel like it when I use the meat in a meal. If I make a large package for a gathering, I put the thawed meat in a crock pot early in the morning , set the heat on high until its pretty darned warm then add two cans of Campbell's Beef Broth and set the heat down to low. This gets served on buns with all the accompaniments served on the side so people can make what they want.
My thoiughts on actually smoking a thick chunk of meat....any meat is that the slow process of heat and be a real issue in warmer weather unless a cure is used with the meat. Brisket is the only thick meat I smoke and always smoke-cook it so adequate heat is present to help avoid the bacteria that can cause issues. I've been smoking meat for 51 years and after a couple gut upsets in the early going due to bacteria I don't do an actual smoke on anything without cure being used, except the briskets.