Since both players know the other person's likely strategies and tricks, but have different variations of how to do them i reckon it's a bait game. 1B hold at far distance helps zoning and can be taunt canceled to keep the other dude guessing. At slightly closer range you can set up something to allow the opponent to duck ein but punish with A+B when they think they have a punish on you. Can B+K BE cancel the taunt but still get Ein?
Auto GI can be really useful against delayed ein attacks, or the 4A 214B unblockable set up.
A+B the cracks in the opponents vortex.
If you anticipate 66A+B, 6A will leave them open to 1B(Hold) combo, CE or 1K BE at close range. Make sure to mix with 3A in case opponent tries 33B BE.
If the opponent knows zwei, act like you're setting up 214B UB setup but release ein immediately after (or before, use your judgment) zwei gets into stance. Good damage off ein and the GB attack.
If the opponent has a pattern to their 1B(hold), fuck them up with 33B BE under ein's swipe if possible.
That's all i can think of, and most of it is theoretical.
Prizes for @
Slade and @
ThatDarnNinja for stating the obvious: Fuck all.