Here is my primary BFD2 setup, with the pads I use for HH highlighted. I use the "closed tip" for one hand, "variable tip" for the other. This introduces enough variance into my playing to sound realistic enough. Of course what works for one person may not work for another.
As for choking an open hat, this will happen automatically as you play. For instance, after hitting the open hat, hitting the closed or pedal will choke off the open sound. You can also of course assign the slot choke articulation to a pad to cause a choke, but that eats up a whole trigger.