Which -number weight drop on bats is better?

Number Weight Drop on Bats

It designates the Length to Weight difference - i.e. if a bat's length is 34 in and is a -5 bat, then its weight is 29 (ounces)

It is the difference of the height and weight of the bat.

if you have a 33 inch bat and its a drop 3 it would weight 30 ounces its the ratio between the length and the weight