my personal perfect build for it was.
just either simple 21/18
o 24/18
u dont need the over strengt,the maul crushthroughs evrything already at 21 str and the agi make su faster which is great with an slow wep,and makes it able to stick to ur teammates which is needed cuz its an support weapon, it opens an new fighting style with it( hold ur overhead holded and walk back forth and to the side a bit untill ur enemy panics and slashes he should miss cuz your out of range and then u suddenly charge forward with the overhead but most people wil try slashing again so ul just get an cleaar hit to his face.
hope this info helps you:P