What is the procedure for taking down Titans?

Beating Titan

• Ultra stun (stun 3x)

• Then give him a beating (quick 8-hit combo)

• Climb on his back allowing you to ride him. Do this a few times and he's down (3x)

  OR

• Keep punching and then instead of climbing on his back, Batman will defeat him.

Let me start by reciting points from previous answers (that I've confirmed):

• 8 hits per repetition (rep),
• 3 repetitions to down, and
• only one rep to down if they're last.

Now, here's my additional research:

• A rep is defined by one unbroken instance of the Titan being stunned, characterized by hunched posture and nonhostility.
• I've only confirmed 8 hits per rep for Catwoman.
• The only way to detract from a Titan's health is by the slow-motion, 8th hit in a rep.
• Corollary: A stray swing from a Lieutenant that hits a Titan does not reduce how many reps that it takes to down the Titan. I forgot to test singular critical strikes that seem to be able to hit unstunned Titans in freeflow, but I assume that such strikes don't actually hurt them either.
• Corollary: Titans can be indefinitely juiced.
• Ultra-stun on Titan lasts about 6 seconds. They shake it off at the end. This was without follow-up hits.
• Strikes extend stun. I timed the stun to last about 7 seconds (probably the same as no hits) after the last hit of a series of strikes that did not end in a slo-mo, eighth hit (tease rep).
• Redirecting (over) a Titan does not reset rep nor stun.
• Ultra-stun does not reset rep.
• The third stun of an ultra-stun maneuver is immune from physical attacks. This is important to successfully stunning a Titan without losing a combo since countering while stunning is difficult.
• Interrupting an ultra-stun with a counter resets the ultra-stun counter. E.g., if you perform two stuns on an enemy then counter someone else, the next stun on the original enemy will not result in an ultra-stun, but instead count as only the first stun of three for an ultra-stun.
• The equivalent to ultra-stun is hitting a Titan with Batman's explosive gel. Catwoman does not have a gadget option/has no alternative.
• Catwoman is not invulnerable to Titan attack in her whiplash special combo (whip-around).
• Aerial assault can protect Catwoman from Titan attack. I think the move is still vulnerable though.
• The moves that can be performed while piggybacking a Titan are (1) normal movement which involves the Titan flailing wildly, (2) ground pound, and (2) Titan charge. To earn the most hits while piggybacking, it is most efficient to move normally then end with a special move (right before the piggyback timer runs out).
• It seems that the fastest way to end piggybacking a Titan is to perform the ground pound/slam/shockwave 3 times. Titan charge/bullrush can be done a little over three times.

If fought in groups, Titans usually take 3 rounds of Stun/Strike to bring down.

It's important to note that when a Titan is left for the end during a combo run, it only takes a single Strike/Stun mix to bring down.