Hey Smokin'brewer - "Welcome to thhe forum!"
I am assuming that you have seasoned your smoker and all that good stuff. Yes, it's ok to lower the temp over night. I usually set mine at 180˚ and crank it up to 225 ˚ in the morning. Using 4 - 6 oz of wood will work though you may want to do just 4 for your first smoke. Better to start off low than to over-smoke and ruin the day.
I enjoy hickory, oak & pecan with brisket. Many use Mesquite - but watch it as this wood can get bitter.
Take it to 195˚ internal, wrapin HD foil (might add a cup of beef broth/stock) & let er rest for at least 1/2 hour - 2-3 hrs if possible.
Let us know how goes it!
![Big Grin](/static/images/graemlins/icon_biggrin.gif)
Good luck...