having it balanced is good but you might want to try making them more unbalanced.
In terms of speed, a heavier upper part might give you a (very) small boost in your forward speed while decreasing your backward speed or vice versa. Another one you might want to try is making one side heavier than the other, making your quick turns on that side to have a larger rotation while decreasing it on the other side (im not sure if it also affects your horizontal QBs, haven't tested it).
Just try formulating them to suit your movement and fighting style.
In terms of speed, a heavier upper part might give you a (very) small boost in your forward speed while decreasing your backward speed or vice versa. Another one you might want to try is making one side heavier than the other, making your quick turns on that side to have a larger rotation while decreasing it on the other side (im not sure if it also affects your horizontal QBs, haven't tested it).
Just try formulating them to suit your movement and fighting style.