Eye round isn't really a pulling roast. It's a slicing roast. You only want to smoke it to medium rare or medium at most. Anymore than that and you will have a dried out chunk of jerky.
A Chuck or seven bone roast is what you'd need for pulling.
http://www.smokingmeatforums.com/t/236400/spun-eye-raost
Bought a 7 bone roast and put it in the freezer for next weekend. Today is leg of lamb. Again, thanks for the advice!