Last night I put a nice size brisket into my WSM. And I smoked it until 199* IT (normally, I'll take it as high as 205*). I had to run out for an hour and didn't want to leave it smoking while I was gone. I wrapped it for a few hours and just sliced a piece off. The smell is amazing as usual adn the flavor is really good; however, it's not as tender/butter soft as I like it.
In order to get the meat to be more tender (butter soft) should I put it in my oven at 250* and let it cook a bit longer. If so, I assume keeping it wrapped in foil and perhaps putting some beef broth in with it.
Beef is not as forgiving as pork. You can overcook a butt and it'll still be good. Overcook beef and you have leather.