If you look at a rag joint its sort of like a u joint, it just has a felxible fabric disk instead of the metal center link in a u joint
The rag joint has metal sockets on eash side with 2 ears like the 2 prong "yokes" or shaft connections on a u joint. The sockets on the rag joint bolt to the rag joint disk at a 90 degree angle from each other like a u joint
One mount attaches to the steering column and one ataches to the rack shaft.
Each connection has 2 bolts that correspond to the prongs or yokes on the u joint.
If you look at the rag joint you can observe the relationship between the steering column "yoke" and the steering rack "yoke". Just position the u joint the same way
The advantage of the rag joint over a u joint is that the rag joint offers a flexible connection and the rotational speed it transfers from the input to the output shafts remains constant as the joint rotates like a cv joint.
Rag joints werent used on fords becaues they were cheeper but because they are more flexible and able to accommodate steering shaft to rack misalignments, provided a smoother feeling at the steering wheel and a more precise tranfer of power from the input to output shafts.
As a u joint rotates it tends to "clunk" over at 90 degree angles resulting in acceleration and deceleration of the output shaft. This increases as the angle between the input and output shaft increases. That is why modern front wheel drive cars use cv ( constant velocity) joints rather than u joints on the front wheels.
To check this out get one of the u joints used with socket wrench sets and connect a extensions to both sides then hold the extensions at a 45 degree angle from each other, rotate one extension and feel the effect on the other. Then increase the angle and you will find that the u joint starts to " "clunk" over and bind up as the angle increases.
Drive shafts arent as critical as they tend to stay pretty much in line with just a few degrees of ofset.
Also u joints need to be lubricated or the needle bearings will wear and disintegrate and the steering will have play and tend to "clunk" when the steering wheel is turned.
The .030" or so slack in the cups of a u joint due to worn out needle bearings usually resultsnin about 1/2 " o4 more play in the steering wheel. Not critical but annoying.
Unless you are REALLY stressing the rag joints the best solution may be to just replace the rag joints, check them regularly and replace as needed.
Due to the rigidity of an all.metal u joint misalignments may cause them to wear more and fail prematrely.
I drove MGBs for years and the steering u joints were a constant source of problems resulting in play in the steering wheel.
Just my opinion..