Always use 30 min. epoxy on high stress/value control surfaces. The long drying time allows the glue to soak into the wood creating a strong bond that CA cannot match. Epoxy is also flexible making it less likely to come loose.

You can also poke small holes in the vertical stabilizer as well as in the fuselage where it attached to increase the bonding area for the glue. This technique makes little "pins" that strengthen the area.