Vs. Balaur in Abyssea - Konschtat:
840 base for most Breath WS, 1200 base for Hurricane Breath
756 Breath with only Ancient Circle (0 JPs)
747 Breath with only Ancient Circle+1 (0 JPs)
732 Breath with only Ancient Circle (Master)
723 Breath with only Ancient Circle+1 (Master)
1056 Hurricane with only Ancient Circle (Master)
1044 Hurricane with only Ancient Circle+1 (Master)
Vs. Sabotender Royal in Reisenjima:
With DT-50% and Plantoid Killer+23,
Full: 250, Taken: 116 (-53.6%, -7.2% from half)
Full: 500, Taken: 232 (-53.6%, -7.2% from half)
Full: 1250, Taken: 581 (-53.52%, -7.03% from half)
With DT-50% and Plantoid Killer+13,
Full: 250, Taken: 120 (-52%, -4% from half)
Full: 571, Taken: 275 (-51.84%, -3.68% from half)
Full: 2000, Taken: 960 (-52%, -4% from half)
Vs. Cactrot Veloz in Eastern Altepa Desert:
With DT-0% and Plantoid Killer+10,
Full: 125, Taken: 120 (-3.2%)
Full: 625, Taken: 606 (-3.04%)
Full: 875, Taken: 848 (-3.08%)
With DT-0% and Plantoid Killer+20,
Full: 125, Taken: 117 (-6.4%)
Full: 500, Taken: 470 (-6.0%)
Full: 875, Taken: 822 (-6.1%)
Stone vs. Eschan Puk 109 (Escha - Zi'Tah)
(Fixed INT and MAB, I forget how much)
Dragon Killer+15 base
Normal: 516
F.Body: 552 (+6.97% over Normal)
Circ+1: 603 (+16.86% over Normal)
Bod+AC: 699 (+35.46% over Normal, +26.63% over F.Body, +15.92% over Circ+1)
Stone II vs. Eschan Puk 109 (Escha - Zi'Tah)
(Fixed INT and MAB, I forget how much)
Dragon Killer+15 base
Normal: 789
F.Body: 844 (+6.97% over Normal)
Circ+1: 923 (+16.98% over Normal)
Bod+AC: 1070 (+35.61% over Normal, +26.78% over F.Body, +15.93% over Circ+1)
I had some older tests that I didn't fully label and can't make sense of now, but the conclusion there was that testing nukes vs. NMs had Ancient Circle providing +10% normally and +11% with AF.
Conclusions:
Against regular monsters, Circles provide +15% Damage Dealt, -15% Damage Taken, +15% Killer effect (+2% to all +1 from AF). Against NMs, these effects are reduced to 10% (+1% from AF). Some old testing has subbed Circles as 5% for regular enemies. Didn't test subbed Circles vs. NMs.
Max JPs in Circle effects reduce damage taken by 24 instead of 20 for some reason, so likely Floor(JPs * 1.2).
Founder's Breastplate adds Floor(Killer/2) damage dealt and taken vs. regular monsters, which are multiplied by the bonuses received from Circle effects and the effects from Gear (which means it breaks the 50% cap on regular DT gear). Floor(Killer/3) vs. NMs. I assume BST Empy body is also weakened on NMs but don't care to test it.
Also part of my old notes is a routine for Damage Taken checks:
Equipment > Tusk/Scherzo/Sentinel/Fan? > Phalanx > Circle > Circle JP > Stoneskin > Manawall
Didn't test Scherzo/EA or any of those JAs, but Barrier Tusk is definitely applied before Circles but after Equipment. Also have yet to test where Founder's Breastplate works into this, but I'm guessing it's between Phalanx and Circle JPs. If I ever bother to go back into these tests, I'll be sure to check Scherzo since I actually care about that.
Also also had a test on Dragon Breaker vs. a pet Wyvern in Ballista:
Duration: 180 + JPs (halved and floored vs. NMs)
Potency: -20 Accuracy, -20 Evasion, -20 Store TP, likely -20 Magic Acc. and -20 Magic Eva. as well
Potency may be halved on NMs but I probably won't test it. Wyverns in Ballista count as regular enemies.
Lastly, the power of ??? Needles -- at least from Sabotender Royal -- seems to be based off of the amount of damage taken in a certain window (like Assailer Chariot's Discoid). His pattern is apparently:
1000 or 2000 Needles
2000 or 4000 Needles
10000 or ??? Needles
Chupa Blossom
He'll use the stronger version if he takes a certain amount of damage between WS, but no idea as to how much.