In the Pitts, a "proper" recovery takes about three turns while you wait for the nose to drop, the airspeed to build and the rudder to get some authority.
Having not flown a Pitts, I would presume this would be for the uncertified version, as the certified version would have had to demonstrate being recovered from a one turn spin, in one additional turn to be certified at all....
Flat spins (which you should never get into by accident, if you're in CG limits) are a different matter. It's kind of fun to watch the airspeed drop to zero.
Yes, I have experienced these during testing in both the Cessna 206 and 208B. It's a weird combination of benign and terrifying to be looking down at the horizon, with the control wheel pushed all the way in - waiting for something to happen. In each case, it did happen, just the world was going around a bit until it did!
The difficulty for spiral dive training is that we can take stalling and spinning to the fully developed stage but not the spiral dive recoveries, at or around the aircrafts vne, where it matters and with the apparent control lock
Yes, understanding that not only does the speed build up, but also the G, as you pull to recover (not thinking to roll out first). High speed and G together are a very bad place to be - particularly without a G meter!