Wow, wouldn't it be so great if you could set AI to block left or block right (and not invert inputs on cross up)
ON a more serious note. 33 (and i guess b13) are known to have cross up properties. but timing can be tight depending on the set up/delayed wake ups. The other down sides are your opponent could just hold down to block. and the 3 part of the string is unsafe/punishable/has a gap.
I personally prefer jumping over into backwards fc (you can even whiff a j2 for style points before the fc)..... from fc, dTHEN2 to land on the outside of the corner/go into combo. i go into 13 fc as its good blockstring/corner combo starter.
or (after kd) 13 backwards fc, then you can falling 2 on them. Its ambiguous enough that I confuse myself some times. And prefer to follow up with 21 (and hit confirm into a special off of that, or frame trap into d1 bf3)