I picked up the wooden camera half cage for the bmpcc. I believe it, or something similar is must-have. BH was selling the Wooden Camera for 50 bucks a while back so it represents a nominal investment. However I think it's mandatory, having a two point contact makes a big different, the bmpcc just felt too flimsy mounted cageless. The profile of the lens also could be problematic due to clearance issues.
Kinotehnik loupe seems to be a necessary evil for budget shooters. It's not particularly well engineered, there's slight bowing in the plastic in the edge that mates to the bmpcc which can cover the cam's (too small) data info. You should considering biasing the mount AWAY from the data readout to avoid obstructing critical info like ISO etc. The company's tech support is non existent. Until Zacuto releases their loupe, I'm not sure if there are other, better choices.