thats one of the problems i had, maintaining temp. i just keep playing with my smoker till i get it down, and i still dont. what has been working well for me, is when i started using a combination of wood and lump charcoal. if the temp falls get some extra charcoal hot and put it in the firebox, when the temp is droping and the wood is prety much burned up i will just add wood. it all just depends on what i need and what my mood is.
on the brisket the smaller end of my brisket is usually a little tough, or should i say not as tender as the fattier side, but it dont bother me. i have read a few posts in here, witch may help you, that explains either to smoke it for a while (4-5 hours) then wrap it in foil till its done (around 185*+ or 205* if you want to pull it) or cook it to around 175-180* then wrap in foil and stick in an ice chest wraped in blankets, towels, pillows, what ever you want to keep it nice and warm, it will still cook for a while (i think they said up to 4 hours) and become more tender.
i think the only hard thing about brisket is my attention span over 12 good hours. its hard to keep me focused all day witch is why i usually have to take at least one small break thru out the day :lol: