I was not attempting to test torsion bar stiffness, I was just did the "fender bounce" out of curiosity after I installed the bars, and was using the same fender bounce on my Scamp as a reference, so I am not sure that I agree with your statement that it was meaningless. I performed an impromptu "experiment" on 2 similar vehicles, and observed 2 different reactions to the same input. I also took into account the blown out shocks as a factor in the differing results.
Especially with 318 torsion bars. Which pretty much ruins your "test". The 318 bars will seem really stiff if you bottom out the suspension on the bump stops mid-travel.
Car was at stock ride height with the stock torsion bars and regardless I did not perform the bounce test on the car with the the 318 bars, I used my Scamp with 1.03" bars as the reference, and it has trimmed bump stops with plenty of wheel travel, because I might not be the sharpest tack, but I am sharp enough to trim bump stops, and not drive around with the suspension sitting on the bump stops.