I am thinking about getting one of these lovely guns in a few months and I have a few questions. I would want a viper as I like the stainless steel and I would want it in a pistolish format. What would be my best option for stockclass and I assume that the 12g would go in the bottom tube by the pump handle right? What is the efficiency like on these and how easy are they to service the bottom tube. Also how much do you think that the rig I described would cost. Any other info would also be appreciated, THANKS!