To be honest mate you are too high combat for anything else than 60 attack Peity pures and zeros will just rip you the whole fight.. Your literally trying to survive then ags spec it's ridiculous. Best bet is to make a 60 attack account weather it be 60 attack 1 def or 60 attack zerker - tables can turn for once then too..
Personally 75 attack is boring and you gain too many combats, even as a zerker I just don't see it (personally). Ultimately; its your choice