"at what height do you go-around from when practicing a PFL".
50-100 feet. It's the 0-500 feet bit which is the trickiest and there's a bit at about 200 feet on every glide approach of mine where I think "Yes! I'll easily get it in from here, I'm much too high actually" and then I drop full flap and then I'm kinda too low.
I tend to cruise fairly low and, in a way, PFLs are easier from a low height because you can't change your mind.
QDM