to me is seems like the 9" double end bag getts more action than the little 7".\ Theres quite a few different ways to gain speed. I usually do a workout with a boxing timer that goes off every 3 minutes with a 1 minute break and go from one bag to the next. The baggs I have are the speed bag, double end bag, heavey bagg and the coaches mitts. I'd do 2 setts on each bag, which will give ya 8 rounds -------------------- Author of "WarriorRage KickBoxing by Scott Bolinger" www.warriorrage.com