I just got my Ruger Blackhawk (same as the Air Hawk just a different stock) and I used an Accushot 1 piece medium height mount and it worked like a charm. My rifle doesn't have barrel droop but if yours does you could shim the rear scope cradle with 1 or 2 pieces of 35mm film negative,, I've done that on a couple of my RWS rifles that have droop and it works great. You just have to be careful though when you"re tightening down the screws that hold the scope into the cradles as since the rear of the scope is a little higher you could damage the scope tube. Shimming of course is a personal choice, some guys don't use the technique, but I've never had a problem with it and it's saved me quite a bit of money. The Beeman 5039 scope goes for around $60 bucks,,, the accushot mount is $16 bucks....... Anyway, another option for you to consider....
Jeff