I agree with the sado strength block set up. As someone who has made it to lv 68 and seen the lv 78+ top players on my server playing, almost all of them use sado. Of which they had both sado and yachiru so they had experience with both before making their choice. Strength and block is a good way to kill of supports early on.
Yachiro is completely useless as a Vanguard, she doesn't have block and her dodge is really weak.
I've met a bunch of Yachiru so far and none of them could dodge half as well as sado can block, and i don't even have that good hit stones in my gear, just average stones i got randomly.
I like Yachiru so i voted for her, on my server the number one player has a monster Yachiru ... He can beat ppl whit full hp whit only Yachiru (tested on me .. and i am not weak and i have plenti of hit stones myself).