FFTA2 damage calculation

[Ezzeth]

Sorry if I came out as rude, let me get to the point. I am a beginner in hacking and I found that from somewhere in this forum it says:
Magic damage formula = (Base power + Magick - Resist/2)*.75
If I use magic with 2x dmg, does it calculate like,
this: 2*(Base p + Mgc - Res/2)*.75
or: (2*(Base p + Mgc) - Res/2)*.75
or: (Base p + 2*Mgc - Res/2)*.75 ?

I also found that if your ability has no base power, then it uses your weapon power as the base.
Is it true? Does it also work for magic abilities if I set the weapon to have magic stats?

Edit: Additional question
Does bypass defense setting also bypass resistance?
If I set a base power, do attacks that deals normal damage twice have higher damage than dealing twice damage once?