Pilot DAR
The first evidence of trouble is the anomalous roll left, and I am having trouble matching that up with a fouled or broken TT. There is some evidence of Pitch change prior, and that could be W/T, but again, I Think the snap left and Nose Down shows a high speed STALL. If you look at Pitch just after this slight roll enhancement, you'll see a pronounced drop in the Nose. The Ghost carries this Pitch down only briefly, and starts its ascent right away.
I think Jimmy was tighter to the pylon than Strega, Voodoo, and would have passed their W/T 'above' (actually, "inside"), as it settled outward. This upset looks very much like a too-tight turn, a quick STALL, and autonomous recovery. The fuselage distortion is quite indicative of an overloading downward moment, a result of exposing the tail to extreme aspect at this remarkable speed.
For me, it is easier to see the Trim Tab fracture as a result of, rather than a cause of, the climb. Again, it was in the airstream in the up position to begin with, and its exposure would have been at an even steeper AoA than the HS in the brief STALL aspect. The elevator would have seen some airstream relief in this aspect, and the HS would have been the source of the energy that overloaded the Fuselage in the area of the Buckled skin.
To answer your question, if the NOSE drops, the G would be quite negative, and a starting point for the ensuing positive G associated with the climb. As a reversal, I consider these values to be additive, and the damage resulting quite alarming. Both to the pilot and the airframe.
21G? No comment.