The Posse's Gary Jacobson talks business with Pinkerton's Barbecue owner Grant Pinkerton in the bar at his north Houston restaurant. (Photo ©Chris Wilkins/Texas BBQ Posse) The Posse always enjoys going to Pinkerton’s Texas Pit Barbecue in Houston. The food is great. So is the bar. And the conversations can be stimulating. For a young dude, owner-pit master Grant Pinkerton is full of wisdom, barbecue and beyond. That’s gotta be one of the factors that attracted the attention of Forbes magazine, which last November included Pinkerton on its prestigious 30-under-30 list of “youthful visionaries” who are changing their industries. Forbes calls…