If you do a regular recovery as soon as you feel the stall/spin breaking away, 500' is plenty. Not, again, that I'm recommending going out and trying it at that altitude.
Not wishing in any way to dampen a thoroughly entertaining read, but has anyone, witnessed, completed, heard of, a spin recovery, in the circuit, from 500'
I have read hundreds of reports where, let's say, all,perished from a loss of control/spin in, within the circuit pattern.