3 hours should be good!
At an hour and 1/2 per pound (general rule) for pork....2lbs should take about three hours which is what my fatties usuaaly take to heat to 165 internal temp so you should be good starting them at the same time.
As for a rub.... that is about as wide open and ended question as has ever been asked.... you will get about as many ideas as you get posts... LOL
A good basic rub can be found on the left hand side of the forum's main page under recipes.... and then follow through to the pork section.
I have used it and it was a good place to start.
Good luck and don't forget to q-view as we like to celebrate the success of other almost as much as we like to celebrate our own!