Aw, your poor kiddo - hope he feels better soon!
As far as experience w/ surgery, my Wylie had surgery about 2 years ago and it went so well. He'd had LP for many years - but it wasn't until he was around 8 that he started lifting up one of his legs - we knew then it was time for surgery. The first few days after the surgery are rough, but then they really do start to snap back. The rough part is that their legs are wrapped and it's hard for them to pee - you have to use a towel under their torso to keep them lifted up, helping them go potty. Wylie is as active as ever - still wants to run etc - and he has no limping at all.
As far as how long to wait, I just have no advice there.
If you have the surgery, I hope it goes well
!!!