Oboy said:u just need 51 compsite spec to not get any variance while using CS styles. So 50 slash is useless if ur not planning using slash styles (why anyone wanna do that)
so spec 51-rr-11 slash and u will be fine.
If you read what bigchief said above, higher melee spec also affects lvl 50 styles from other lines (cs/dw).
So, best possible Dual Shadows damage is reached when you spec 50 slash