Heh, actually, I've been mucking around with the zodiac stuff in FFT a LOT lately. It seems arcane at first, but once you get started it's not hard at all, especially since you can retrieve any unit's compatibilities from the interface itself during a battle (select unit, then "status," then hit select and pick the unit's zodiac sign).
Here's the math behind chance-to-hit spell effects...
n% = (Caster Faith) x (Target Faith) x (MA stat + innate spell accuracy) x (zodiac modifier)
Caster and target Faith can both be anywhere from 0-100. Individual spell accuracies are anywhere from 100 to 250... Raise has an accuracy of 180, while Death has an accuracy of 100. Zodiac modifier is 1 for neutral, 0.75 for bad, 0.5 for worst, 1.25 for good, and 1.5 for best. Zodiac compatibility can make hitting a target with low Faith a
sure thing.Let's say your Time Mage has 75 Faith and casts Haste on your Ninja, who has 50 Faith. The two have Best compatibility - opposite gender, opposite sign. With neutral zodiac, this would mean a 69% chance to hit; with Best, it bumps to just over 100%. Your Ninja still retains 50 Faith and therefore decent defense against enemy casters. Heck, Shell has 200 accuracy, so that's even better.
Party coordination is a little complex, but it's possible to organize your party so that every effect that matters has decent to excellent chances to affect its intended target. Even more useful (and easier!) is knowing which zodiac signs your chance-to-hit casters favor... this can allow you to pinpoint enemies that can be Sleeped or Silenced immediately, or even just outright slain via Death or Petrify.
Agrias' sign is naturally Cancer, so having Yin Yang Magic equipped, my Agrias can easily affect Scorpio and Pisces targets (and male Capricorns are even better). Since my Ramza is a Pisces Priest, I know I can Pray Faith on him easily.
I'm done nerding... for now.
![Cheesy :D](https://elementscommunity.org/forum/Smileys/solosmileys/cheesy.gif)