B1xx mb is actually very good. I'm having a ton of fun with this variation. Theres a lot of bullshit that goes along with it, especially when you mix in b14.
B14 mb cancel is +1 which is an amazing position to be in after a hit confirmable, full combo string. The only thing to respect is d1 but it's still a good spot to be in.
Ending combos with st 4 xx mb3 is a pretty good way to get a restand with good damage. At plus 11 b1 has to be blocked. Canceling the b1 into mb will prevent whiffing b14 on jump attempts.
I love sin blade btw.