Your options are relatively few, so that makes the enchooserating process more easier: Indy 169s, Ace55s for your 9.1 and the 66s for the 9.56, or either of the two new(er) offerings out of Ermico in SF... Venture 6.1s or the Thunder 161s. For me, if I'm going China, it's the Ace slabs; if I'm feeling made in the USA only, I'm going with the Thunders in the "Team Hollows" version. You get that taller geo for better clearance on bigger wheels thanks to the cast base plate, and all of that tasty, hollow, weight saving, goodness.
Plus, I don't care what people are saying, my Thunders feel like greased butter when grinding concrete. ...'Course, anything does if you're rolling fast enough, so just get what you feel like trying out & go faaast, I guess.
Hugs & happy shreddage to you.
EDIT: did Cigs say Krux?!? I genuinely had no idea.