Definitely not ATC shove spot as default. In nash I would assume something like 70% but lets check what HRC says:
I assume this is 9man sng? Ok well this is what FGS1 would say: http://hands.holdemresources.net/?id=w9bypasurvd7
So SB would shove 54.5%, 22+ Ax K2s+ K5o+ Q2s+ Q8o+ J3s+ J8o+ T4s+ T8o+ 95s+ 97o+ 85s+ 87o 74s+ 76o 64s+ 53s+ if SB call 24.3%, 44+ A2s+ A4o+ K8s+ K9o+ QTs+ QJo. To me calling range doesnt look that tight that we could often tighten it much.
Anyway if BB call 20.8%, 55+ A2s+ A5o+ K9s+ KTo+ QTs+ then we could shove 84.6%, 22+ Qx+ J2s+ J3o+ T2s+ T4o+ 92s+ 95o+ 82s+ 85o+ 72s+ 74o+ 62s+ 64o+ 52s+ 53o+ 42s+ 32s.
Finally for any2 shove to be +EV BB need to call 18.7%, 55+ A4s+ A7o+ K8s+ KTo+ QTs+ or less. Now hero probably has best idea of player tendencies in general on these games.