Ideally the tow point should be at the centre of gravity for both the towed plane and the towing aircraft.
The tow connection on the towed aircraft is normally slightly forward of the CG point to aid is tracking on take off but can reduce directional control effectiveness the further it is from the CG point.
The towing aircraft will be difficult to control if the towing point is too far from the CG point. it the extreme, (if the tow point is at the tail of the aircraft), the towed aircraft position can cause control issues. For instance if the towed aircraft is high and climbing faster than the towing aircraft the towed aircraft will try to pull the tail of the towing aircraft upwards which can cause violent pitch down and if not corrected a crash of both aircraft will ensue.
I recommend that a pair of tow points be fitted to the aircraft on a Tow Bar which is free to pivot through the CG point in the fuselage. A "Y" tow cable setup connects the tow bar to the tow point on the towed aircraft. This bar with central pivot allows rudder function whilst taking off and in flight.
Both aircraft should have the independent ability to disconnect the tow cable in an emergency.
Hope that helps!
Have fun!
