For what it's worth, I added the extra light bulb in each lens for the rear lights when towing. Adding the bulb involves drilling through the plastic lens and inserting an extra bulb socket. This eliminates having to tap into the wiring on the car leaving all the lighting wires in tact. Worked very well and was easy to do. I decided to put the car on a dolly rather than flat tow it. Read some horror stories about blown out trannies while flat towing.
If anyone want to see pics of this lighting set up, let me know.