True but a quick reversal to extreme positive can do nasty things.
Agreed but this is unlikely to be a factor - while several physiological factors can affect G tolerance by a surprising amount, the figure and subsequent -ve and +ve spin modes are not particularly high G for this level of pilot. An outside/inside 'S' is much more likely to switch a pilot off. However, although nothing can be discounted, we will probably never know. Not least because the AAIB obviously have no FDR data to go on. In order to rotate the aircraft around the pitch axis, pro tumble inputs tend to produce a negative spin once the tumble decays, and subsequent recovery can become an erect flat spin. The figure can be difficult to consistently repeat and the resultant spin modes burn height. David was highly skilled at tumbles and very current but sadly unlucky on this occasion. I am very saddened - he was an absolutely lovely man who contributed so much and will be sorely missed by so many.