Since the plane is towed backwards, the rigidity of the tail support has to maintain the tails position from sliding sideways, if you wanted to get real creative, think of a light trailer's leaf spring , now invert it, instead of the axle being bolted to the spring, a saddle that would connect to the rear Dorsal Fin/hitch mount hole in the tail, if your not sure that will handle side loD pressures well put 2 linkage rods, one on each side to control side loads,
Im on my cell phone right now or i would draw an example 👹