Her b1 is 18 frames. F3 is 19 slide is 21. So as far as mixup b1 and f3 will be your go tos from the range of the untechable u3. I just hit the lab against scorpion and set his wakeups to random. I don't believe the shorter combos Have any benefit really but what they do is give the opponent more opportunities to do wakeups and more opportunities to guess right on a block. Also some characters have wakeups that I don't think KF can even do anything but block like supermoves, flashes bf2 or shazams torpedo. There are more I'm sure but you get the idea. I think when fighting these characters the metered vortex would be the way to go. I'm almost considering doing a wakeup punishing guide