I'm doing 3 pieces str 1 piece blk. Though I'm going to have 60 agility, which I feel "makes up" for blocking.
Whatever "ratio" that puts it at, I dunno. Something like 1.1 : 1 I guess down the road.
While DTs are going the agility route, most are still strength beasts, and I think that the best combat to the agility DTs is to round out your build instead of sacrifice strength.