What is it that you are trying to accomplish and what is the age group. In youth baseball there are benefits to both. If you are able to control the heavier bat and still get it around then go with a heavier bat. But if you are not able to get around on the pitches and the barrel is dragging through the zone with the heavier bat definitely go with the lighter bat. The heavier bat will generally equal more power and they do for the most part have larger barrels, but you have to be able to control the bat.
What age group... How strong are you? Can you get around quickly with the heavier bat? If not, it's not so much the size of the bat but the speed of your hands and swing. Keep your swing speed up, and use the lightest bat for your age group. If it's too light, then go 1/2 - 1 oz up and see...
Great question. If you hit a ball with the same bat speed, large bats are better, but the question becomes can you create enough bat speed with a larger bat. Babe Ruth used a 45-50 oz. bat when he played, but pitchers didn't throw as hard then and had more time to get the bat through the strike zone. Now a days most MLB hitters use bats between 32-37 ozs. Pitchers today in general throw much harder then they use to and to create bat speed players have when to lighter bats. Big guys like Mark McGwire can get away with using heavier bats, he used a 35 oz. bat, Bonds used a 32 oz. bat when he his 73 homers. One of the first great hitters to use a lighter bat was Ted Williams, he used a 32 oz. bat. So to answer yur question, I use my radar gun with younger players and test their bat speeds using different size bats and have them use the one that creates the fastest bat speed.
well, it kinda depends on how fast the pitcher is, and you upper body streanghth, if the pitcher is fast, use a lighter bat so you can swinger faster, if there slow hit with a heavy bat, i usually have three bats a lightwieght, in between, and a heavier one.