Rate of change of direction (itself) will not 'give' G - an ac rating at (say) 20 deg/sec could be experiencing (say) 3g or 9g depending on how fast it's going.
At 90 deg AoA the ac is unlikely to be doing 300+ KTS - the speeds involved at these 'bizarre' AoAs are more likely (IMHO/E) to be double figures (or low three figures).
A very impressive machine :-)
Ray