5a is faster. Therefore less punishable on whiff and works in all windows 6a does + more.
If using 5a as opposed to 6a doesn't make sense, does using 2b over 3c make sense?
All c's are stein-cancelable on block, as well as >SoD, and 2c is IAD - crossup j.X on block (b and c are both overheads, +crossup is an added bonus). If your hitconfirm to trip fails, just get out and set up another pressure string.
Her pressure feels like it has gaps when you're controlling it, but it's actually pretty tight, linking together strings is the only part that requires a lot of heavy thinking.
You need a fast frame attack in every matchup, 5a is pretty much the fastest, and Origins, like any textbook DP, is very very unsafe unless you impliment it perfectly.
So 5a
+Fast
+Hard to punish
+Hitconfirms into 2b>xxx
+Gatlings into almost every normal
+Works in neigh every window