Old post, but I just towed an MGA about 200 miles on a UHaul tow dolly. I have a TR-3 to tow the same distance.
Some other websites, folks explained the problem with backwards towing. Apparently, it's hard to keep the front wheels tracking straight, which results in the car swinging back and forth. I didn't tow it that way so I have nothing to add about that.
What am I doing different with the next tow?
1. I'm getting new tires for the rear wheels. I left the almost 40-year old (but garaged) tires on. I had no problem, but now I feel I just got lucky with no blowout. I'm pretty sure a flat would leave the rear of the body in contact with the asphalt. Gonna mitigate that threat with new tires on the back.
2. going to disconnect the drive shaft from inside the car instead of underneath. Not sure about the TR, but I felt pretty stupid the other day when I was cleaning out the cockpit behind the seats and saw the disconnected driveshaft and differential in plain view and easy access. And I was crawling underneath to disconnect it.
3. Probably going to drive slower next time and leave earlier in the morning. I want to finish the tow during daylight. I could see the wheels of the tow dolly in each side mirror, and I could see the windshield of the MG through the rearview mirror. However, I towed it at night and couldn't see the MG at all unless there were other cars or street lights.
If you use a UHaul tow dolly for an MG or TR, bring a floor jack to raise the front end from the side. Slide the dolly in place and lower the car with the jack slowly. Leave a little weight on the jack so you can lift the tongue to connect it to the hitch. Then lower the jack the rest of the way and remove. The pull out ramps on the UHaul dolly are too wide for the front wheels, but the MG sat nicely on the dolly once it was in place.
Good luck.