The moment arm up (or down), from the tow ships CG to a tow hook directly above, would be quite short....... not much more than say 4 feet. I would think correcting for pressures applied at 48” would be well within flight controls to compensate. Constant back pressure could be trimmed out. In the RC world, the tow ships are normally quite stable, as is Glider..........problems arise when too much pilot input is applied on either end of the rope! Guide wires from the top of the rudder fin to the tip of both stabilizer tips could keep the tow rope away from the tows tail feathers.
Just thinking outside the box,
JJ