Hi Pavel,
I've been thinking of making a "dry Jack" as well. I think the pepper and cocoa rind treatment is intended for long aged cheese, so think age for a year type thing. Because of this, it wouldn't hurt to reduce the floc mutliplier a touch.
I believe it's a mixture of cracked black pepper corns and cocoa powder, but I don't know the ratio. I would think this doesn't get added until
a month or two after the make though. I'm looking forward to finding out the details as well.
- Jeff