You will need to turn finals a lot higher than 500' to be able to recover a spin.
Hmmm... I'm certainly not advocating low level spins, but pretty much everything I've spun recovers from a one-turn spin in about 500'. And that's one full turn. 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.
The problem isn't that it's impossible to recover an incipient spin in less than 1000', it's that most people have never experienced one and so aren't spring-loaded to start the recovery, and probably go through a significant panic time before they recall some vague, distant memory of what they're supposed to do. And that WILL kill you.
Which is why imo getting some spin training (and other unusual attitude stuff) is a REALLY good idea, once you have a couple of hundred hours under your belt. (It is dangerous though - it led me to a seriously expensive aerobatic habit).