[editor-surveyor]

>> “A tau cross would have the crucified individual’s head above the crossbar.” <<

.
An obvious physical impossibility. What would hold the body up?

The sag of the arms and shoulders would place the head at least a foot and a half below the bar to which the wrists were nailed.

Ever done chin-ups? does your body just float up?

[MarkBsnr]

>> “A tau cross would have the crucified individual’s head above the crossbar.” <<

. An obvious physical impossibility. What would hold the body up?

The whole thing is to make the individual strain to hold himself up else he will suffocate. Crucifixion was not designed to do anything more than to try to get the maximum suffering by suffocation. The nails just ensured that the person didn't get away easily, and also in rather painful fashion. And the feet were nailed in place as well.