Picked up cheap a Model 12 Heavy Duck that is in excellent mechanical but poor cosmetic condition. Planning on making it into a useful waterfowl gun and have the forcing cone lengthened & chokes installed. This model has a thicker barrel walls then most M12's. Barrel OD is .880, wall is .085 thick. What are my options for tubes? Ideally id like to use beretta mobils as i have a full set on hand or browning invectors.