Very useful option select for Rufus’s high dive kicks (not after knock-down) is s.mp
I find it whiffing less than Vega’s s.hk.
Vega’s back-dash has incredible invincibility when properly used.
crouching+blocking also works on some dive-kick opponents, making Vega hitbox much smaller.
Either way, st.mp will work because the hitbox of Rufus’ dive kick is as shitty as Vega’s AAs.
The trade (you will hardly beat it) is in Vega favor, though. Too bad it has 7 frames of startup and only 2 active.
Crouching is a good and a bad idea at the same time.
Good because you keep your charge, meaning you could ST very early if he jumps or if you see a throw coming.
Bad, 'cause you will be crossed up more frequently, and 'cause opponent will have better frame advantage after his dive. =)