I used to watch the big show cars back up after burnouts and see some pretty alarming-looking front-wheel wobble. At the time I wondered why no one seemed to get all upset about it, just went on about their business and made the pass without the fronts falling off. Upon getting my FED bout 10 years back, and having the wobble thing happen to me I understood what was going on, that the caster that made it stable going forward did the opposite in reverse, especially if you let speed build and get too far from straight at the same time. "Oh-Sh*t" moment but no broken wrists or otherwise. So just keep speed moderate and no wild steering and all is well. It's not like I'm backing up from half-track, anyway.
Just for grins, (not feeling the need for sh*ts), me and the kitten just went and measured the caster on my car, it reads 25' on one side, 28' on the other.
Evidently, old-school thought was that more was gooder, seems modern thought might be that less is more, or at least that less is enough.
Any expert opinions on what is optimum? And any relation to wheelbase or anything else?