15/24 or 15/27 because :
- You will 2-3 shot anyone with a 2h and enough wpf
- The little hit damage difference doesn't mean anything as in many situations the 7/8 ath makes you able to hit twice when with less you would hit once.
And I'm not even mentioning the enormous defensive advantage of high ath (dodge arrows, dodge swings and thrusts, dodge horses, control fights, be a s key hero)