(This is with the caveat you have 3 black and 1 white rod (interchangeable with red rods) with a leeway of possibly 1 black/white freebie from events usually being better anyway e.g. Stardust Rod FFIX, Flail FFVIII, etc)
In my experience:
- Take Wakka or Sazh or Irvine or Fran or Gordon or whoever has synergy (They're all almost virtually interchangeable)
- Give support person some shitty 4* RS knife because I have no ranged weapons (Or, well, PSICOM rifle in XIII)
- Power/Magic Breakdown in slot 1, Mental Breakdown in slot 2, Zeal/Sky Pirate's Pride
- Cycle defensive breakdown, mental breakdown, attack (or defend), repeat this 3-turn cycle
This keeps almost perfect 2x Breakdown uptime. I stick support person in the back row regardless of melee weapon - he's not even there to DPS.
Mental Breakdown + -ja/Meteor/Valefor will virtually always guarantee 9999, and in my experience at the very least 8.5k on Break resistant bosses.
You can spend an action casting Faith to push that to 9999 for 2-3 spells for a net gain of maybe 4k across those turns on break resistant bosses, or cast another spell and do another 8.5k.
The thing to remember about mage meta v bosses is most of them will die in ~8 turns. (3.5 people doing 8.5k a turn = ~240k damage done). This means that if you somehow get a combination close to that and make sure everyone has 8 shots of 4* spells, the boss is simply going to die in 8 turns.
I have:
r4 Valefor
r2 Phoenix
r4 Ramuh
r1 Meteor
r3 Bioga
r3 Waterja
r2 Firaja
r2 Thundaja
r1 Diaga (lol)
It's exceedingly easy to setup 3 casters to have 8 shots each, with buffer coming from 2 r4 comets, 1 r4 Biora which hit for ~5k (Okay, so boss dies in slightly over 8 turns instead) and/or take into account AOE considerations, vulnerability/absorbtion considerations, etc. You can also balance them to do equal damage by juggling around Devotion, Rod Master, Impetuous Youth, etc.
Like I said on the previous page, prepping for Dark Bahamut broke the rest of the game as it is right now lol.
Faith's usefulness is bumped right now if:
- used in conjunction with Lunatic High/Boon, hence getting more mileage out of the action used casting Faith instead of another damage spell
- you don't have enough 5* rods as a non-synergy base and are hitting for 7k or less with -ja spells
- you need to prepare in advance for massive burst
- boss has insane resist and/or Break Resistance and you're hitting for 7k pre-Faith (as with above point)
- used on Meteor guy for AOE situations (applying Magic Breakdown to all mobs one by one are as inefficient in this case as casting faith on many party members in a single target situation)
Faith's usefulness will also skyrocket once the 9999 cap is lifted. (God knows when)