F***ING Shortstacks

We open from:

a) Early Position or
b) Middle Position or
c) Late Position

to 4x the BB and a 20BB shortstacker (unknown) shoves. What ios our calling range in each of the 3 situations?

early pos pairs 99 and bigger, aq,ak.
mid pos basically the same.
Then late pos pairs 77 and up, as well as aj, and maybe kq.

vs unkown I play it tight and wait until I have 50-ish+ hands on him, then I know what sort of range he's on.