EDIT 2: Updated all numbers to account for break imperil lasting until player turn 6. Note that the 200% ATK buff and imperil will fall after player turn 5, before player turn 6. These have been accounted for in the calculations in the spreadsheet. I also added rotation details and some more info to the OP. Finally, the damage per turn table has been pivoted for easier reading.

EDIT: /u/SomeRandomDeadGuy caught an error in my rotation and the DEF break and imperil will last until turn 6 and drop on your turn 7 (but her ATK buff or imbue will have expired on your turn 6). Re-doing numbers now.

I have some very preliminary damage numbers for Tifa which show her lower-bound estimate of damage. You'll see why it's considered a lower-bound/floor model in a bit.

Assumptions

• 1 DEF/SPR target (for comparison to DH's spreadsheet).
• Spark element chain (for comparison to DH's spreadsheet).
• We're not using Crazy Day, World Destroyer, or any 100% ATK buffs prior to turn 1.
• We are using her own imperils, buffs, and breaks (where applicable).
• Her LB and Dolphin Blow do 0 damage - Obviously not true in the real-world, but for the sake of coming up with lower-bound figures, this should work. Adding LB and Dolphin Blow damage really doesn't change her average damage too much anyway (and her LB is not chainable).
• I only modeled her opening rotation. The calculations assume a fully cold start from turn 1.

How did you model her damage output?

I cheated. Sort of. I basically punched in her gear, stats, breaks, imperils, etc. into ffbeEquip, obtained the 1.0x average damage (which does include both hits from dual-wield), and multiplied that against her skill mod then chain mod. This is an estimation of her damage, but it should suffice. Let me know if you see any obvious errors with this method of computation. See the spreadsheet link below for all calculations made.

I also gathered the 1.0x average damage number for each type of configuration (buff, break, imperil, etc. applied and not applied, 60% imperil vs. 100% imperil, etc.) so I can take the correct value for the current turn situation appropriately. You should see those in the spreadsheet.

Lower-bound average damage per turn estimations

TIFA DAMAGE MODELING SPREADSHEET

We'll evaluate 2 types of rotations and 2 types of gear sets:

• Rotation types: LB used on turn 2 vs. LB used on turn 3. Details in the spreadsheet.
• Gear sets: Splash Knuckle (water fist) vs. non-element build (no STMRs or limited time TMRs in either). Links in the spreadsheet and below.

Her LB is dirt cheap at 20 crystals and she has innate 100% LB fill rate.

Rotation with water element weapon

Build (no STMR/limited TMR) - 2070 ATK

Note: A 1H water element fist weapon TMR will be released on Folka's banner named "Splash Knuckle" (125 ATK).

Rotation with non-element weapon

Build (no STMR/limited TMR) - 2118 ATK

Note: Hooray, Thor's Hammer is useful. Note that your rotation here is 5 turns because your imbue will expire on turn 6.

Average damage per turn against a DEF-breakable target

Note: DEF breaks are awesome.

Average damage per turn against a NON-breakable target

Note: These should be comparable to DH's numbers below.

Click for extended 10-turn rotation damage figures posted by u/strawcake2 in this post below

DH's physical attacker rankings for comparison:

Observations

• In a non-element build, 2 out of 5 turns will be used on non-chaining skills: Dolphin Blow and LB. That is 40% of her total turns.
• In an element build, 1 out of 5 turns will be used on non-chaining skills: LB. That is 20% of her total turns.
• She is extremely slot-efficient as she brings all of her own buffs, breaks, imperils, and imbues. She needs no support to function at peak capacity.
• Her 2nd cycle of her 5 turn rotation will yield significantly more damage as she will have max stacks on Final Heaven. Using Dolphin Blow or her LB will not reset stacks on Final Heaven.
• Her actual damage will be slightly higher due to incorporating Dolphin Blow and LB damage. However, Dolphin Blow is a single hit skill and her LB cannot perfect chain (it has high backload on the final hit separated by a long frame gap, kind of like OG Cloud).
• A water element build is not only optimal for damage, but also makes her more user-friendly. Highly recommended to pick up the 1H water element fist weapon TMR from Folka's banner, coming soon.