I don't have any pictures anymore but Reece even made a light duty hitch that only used one bar. You have to remember that these hitches were new technology prior to them people used tow dollies when towing a trailers heavier than the vehicle would support. There were many accidents do to use of faulty/poor designed hitches with no tow ratings. Back in the day many people used hitches that just clamped over the bumper edges and a lot of trailers were towed with a 1 3/4 inch ball. Things changed drastically in the early 60s, people could buy proper hitches with the weight capacity stamped on them at a affordable price and the 2" and 2 5/16" trailer balls became widely used.Custom hitches became available that were designed for a given vehicle that just bolted on, instead of having to go to a weld shop and having a hitch custom made. Back then no one had heard of a car tow rating. Boy did this line of thinking make me feel old.
IF I accept thinking that pre 1970 'vintage" trailers and hitches were lacking, I look at history, trailers Were towed by Cars, no one had a 1 ton diesel truck, hitches hooked onto the roof of some cars, thru the trunk of others. That is what they did. But then is vintage construction acceptable ? Factory stuff ! Really opens up a can of worms.
Ther only one who is a bigger fool than someone who thinks he knows Everything is the person who argues with him.
Very few of the weird trailers were made such as the roof mounts, most trailers were pulled on a hitch behind the car. People didn't use trucks much as the were not comfortable and quiet like today's models also there were no extended cabs and very few crew cabs also no SUVs. It was a different world back then. Vintage trailers that have been properly restored are safe to tow. In fact with today's tires, hitches, and sway controls along with much better tow vehicles they are safer than ever.