I have never towed a car "backwards" with a tow dolly but I can tell you I have tried to tow cars on a 2 axle car trailer "backwards" and it does not work at all - very scary experience and I have a nice car trailer with a Dodge Cummins pickup truck. Not exactly a lightweight set-up.

I would imagine a car on a tow dolly loaded backwards would be a death trap - the hour or so you spent disconnecting the driveshaft would be considered a good investment of time.

Tim