Elemental staffs give a very similar effect as the weather and type of day do too spells, it a magic potency.
Magic attack bonus is also a form of potency some what like elemental staffs, weather and day bonus, but it seems to give more of a blunt or punch effect extending your potential.
Magic accuracy will help with resists! and bring you up to the top of your enfeebling skill potential.
I don't belive magic attack is the best way to go in helping with enfeebles but it dose help.