Got a new DS setup I'm excited to start experimenting with.
I've found that after a j3 (crossup or not), 323 can be unreliable, and if it does whiff it is extremely punishable. Because of this, I only ever do f23-Sword Flip after a successful j3. However, the damage isn't incredible and the last hit of the Sword Flip whiffs. I started messing around with the advantage and spacing that's a result of this whiffed hit, and found that it leaves Deathstroke at the tip of his f3 range, and with enough advantage to allow f3 to hit just as the opponent wakes up. This equals a total of 52% damage (22% + 30%). Even if the opponent block the f3, DS is still left at +10 advantage, though he's just outside throw and d1 distance. However, he's just within b1u2 distance, and at +10 advantage, he can only be stopped by a move 5 frames or faster. Because b1u2-f3-323-f23-Sword Flip does 32% damage, this leads to a total of 54% damage, and is basically completely safe as long as you don't go into Sword Flip after a blocked j3-f23.
Here's a short video showing the spacing and advantage you get after a whiffed Sword Flip:
I've also been working on making DS's block-strings as long, safe, and deadly as possible. After a lot of experimenting, I believe the longest, safest, and most damaging string is f3 (or b3)-f23-b1u2.
F3 is an overhead that's +10 on block and leads to around 33% on hit. B3's not an overhead, but it leads to 36%. Both can be armored.
f23 is totally safe after a blocked f3 or b3 and it's +9 on block. On hit, it leads to around 26%.
b1u2 is totally safe after a f23, it hits low, it's totally safe on block, and it leads to around 30% damage on hit. (I'll get exact damage percentages plugged in when I can get into practice again).
All-in-all, that's a total of 5 separate attacks an opponent must block, with 2 small gaps to entice a counterattack that will get stuffed. If you connect at any point in the string, you can take off a minimum of 26% damage. You can also start with the f23 string after a j3, and still go into a safe b1u2.