hmm. i tried it out with and without the hwiz card.
Having Hwiz card can damage more depending on enemy.
Bolts and other magics have random damage anyways, but tracking the damage caps lowest/highest.
I can say having hwiz card will most probably deal 10-20% more since as other said, most people got low mdef already.
But its not that much, so i better put fsold for stave purposes (to not get stoned and lessen switching equips) or to avoid getting stone when unintentionally meleeing an enemy.
Maya P. is a good way too, but with box of sunlight, it can be altered.