I haven't hinged those vertical stabilizers but a way to hinge parts on a single pivot is this:
Get a length of brass tube and length of brass rod. The brass rod should fit into the brass tube snugly.
Cut off two sections of the brass tube about 1/8-1/4 inch and glue them into the fuselage where the pivot point should go. the surface of the brass tube should be flush with the outside of the fuselage. This will be a sleve for the brass rod to go into.
Put a section of brass rod sandwitched between the two halves of each vertical stabilizer. Leave a bit of brass rod 1/8-1/4 inch exposed, coming out of the bottom of the stabilizer at the point at which it should pivot. Insert this bit of brass into the sleeve in the fuselage and viola. You will have pivoting surfaces.