Hi Scot,
I do not think it will work very well. A hook needs to fit snugly into the standing breech so there is no chance that it moves around during recoil and that it always remains in the same place in the stock. To accomplish that, there will almost always be some leverage upward applied to the standing breech as you remove and install the barrel. To keep the breech from lifting up, original standing breeches had either a lug on the bottom for a cross pin through the stock or a threaded hole for a bolt that came up under the trigger guard. With your design, you would really need 2 tang screws to keep the tang in place as you remove or install a barrel. One screw would have to be near the barrel breech to keep it snugly down.
dave