The above chart is taken from this paper
http://csel.eng.ohio-state.edu/voshell/gforce.pdf
The chart shows a typical person's response to sudden g application and what warning might be available of impending loss of consciousness.
Terminology note: I am using the term grayout to describe the loss of the complete visual field without unconsciousness, and the term blackout to describe unconsciousness. They are the terms I remember from my initial training many years ago.
The red line shows a rapid g onset to a high sustained g level resulting in blackout without warning in a few seconds.
The yellow line shows a high pulse g load decreasing to zero g without causing either visual effect or blackout.
The green line shows a slower g application resulting in visual effects after a few seconds(collapse of the visual field to a tunnel) flollowed by grayout and blackout.
And the blue line shows a substantial period of no symptoms followed by visual effects and finally blackout.
In the GG accident, It appears the extremely high g commences in the left bank and within 1.5 seconds, the right roll rate during the pull up commences, probably indicating GLOC.
The pilot of Voodoo Chile is reported to have debriefed his experience as follows:
...coming down for the start he had unlocked the inertia reel to reach for a switch on the instrument panel...and then forgot to lock it again. After the pitch up, he found himself (in his own words) with his hands on the sandpaper (the floorboard) and the stick stuck between his helmet and shoulder, literally doubled-over in the cockpit.
The pictures showing Jimmy Leeward "missing in the cockpit" probably indicate that he too had his shoulder harness reel unlocked.