Personally Scott, The way I have done it up to this point is I would file the two pieces until they mate up very tight, Then drill & rivet them. Coat hanger works great. Heat them up being very careful in your handling of it before its brazed and sprinkle the borax liberally in the pocket ie. stock side of the joint. Now you could now either cut some brass strips or pieces and lay them carefully in the pocket, or use a stick of brass. Then heat it from the outside of the corner until the brass flows through the joint rocking it slightly to distribute the brass along the whole joint.
Darrin