I see many posts on mods and maintaining heat on smokers with SFBs. My grill is similar to the Char-Griller horizontal offset. Changing the intake makes little to no difference in temp as there are MANY gaps when the lid is closed. Will sealing the lid allow better temp control when adjusting the intake when I set up for indirect heat? I have already extended the exhaust to grate level with vent pipe. Any help/suggestions are appreciated.