Roger---not to get in a fight--but I think that you are maybe not realizing a couple of facts about these front ends and how we got there--now there is hardly anything similar between ifs and beam axles and only a very minute differance between wishbones, split wishbones, hairpins, and parallel 4 links---

ONE factor with any suspension is that the wheel/axle DOES NOT move up and down, but stays in contact with the ground

Wishbones were split in order to lower the cars back then---

In order to adjust castor beyond what they had (remember they wanted to go from a 40mph car to a 140-200 mph car) they cut a notch out of the arms to angle the axle where they wanted it

The guys wanting lighter weight and more at track adjustment went to tubing HAIRPINS with heims so they cutadjust caster plus set axle square with driveline of car.
A car with hairpins-----does not have any different arc(concentric/parallel) for the top or bottom tube--it works as a singular unit with the batwing on the axle---now a parallel 4 link is a different story.With 4link the caster of the axle has a better chance of staying constant thru out the travel

With the split wishbones, hairpins and parallel 4 links, there is considerable binding of the front on suspension travel and also a greater need to keep the axle centered, especially with anything other than the leaf springs/shackles.

Most of these older vehicles have a decent amount of camber which came about from wheel/tire size height etc and using wheels with different offsets upset the issues very quickly (death wobble)