Originally Posted by Magnus
I have to confess that I still don't fully 100% understand every mechanic about summons either. From what I gathered through trial and error, they run on their own gambit when you first summon them. Then, you should ideally wait till the Gestalt meter is almost out before hitting Square to transform into that mode (was there a penalty or bonus for timing it properly somehow, other than to aid you in your circumstantial staggering efforts?), and once in that mode, you could enter various combinations that each cost a certain amount of....'fuel', shall we say, as indicated on the screen. I assume if you ran out of fuel, you couldn't execute the Triangle "final" maneuver, like Odin's Zantetsuken. Or would it occur anyway? I always hit Triangle when I was down to 01 or 00 'fuel'. Am I correct in assuming the Circle ability was always typically magical/elemental in nature? Such as Thunder for Lightning's, etc?
As far as I can see, this is the right way to use a summon:
Almost stagger a tough foe. Summon. Keep chaining alongside your Eidolon and build up the Gestalt meter. Once it's full and the enemy is staggered, hit square (or the X360 equivalent). You can also wait out the SP meter, but beware, when it hits 0, it'll start using up the Gestalt meter. Use the Gestalt form to drive up the damage multiplier, I usually just use Auto-Gestalt, and on the last move, unleash the level 3 finisher. No matter who you are, an Eidolon finisher at 900%+ damage is going to hurt.
An additional use is to summon in order to revive your team. Sure, Renew does that for one TP less, but you have 5 TP, so why not get some free damage alongside the full-heal?