RE: How to recover from a tip (wing) stall?
Basically an airplane must be stalled to enter a spin. If you release the sticks, you usually have done enough to decrease the AOA to below the critical AOA. The airplane isn't stalled, and you fly out.
Why not get really high up, and practice a few spins. To recover, power to idle, ailerons, neutral, opposite rudder, and forward on the elevator to break the stall. It will become a reflex after awhile.
Something we practice in full scale flying is incipient spin recovery. In other words, just as the airplane starts to break (yaw) to one side or the other, recover from the stall. Pitch the plane forward and roll it level. Once this is a reflex, even at low altitudes, you'll be able to recover from stalls. Last but not least, the ultimate confidence builder (for my students who were afraid of stalls), go up really high and learn to recover from stalls without the use of power at all. Fly level, power to idle, then slowly pitch up to maintain altitude, you'll reach the critical angle of attack (pitched up too high), then simply lower the nose and glide out of it without adding power. This may be best done with a buddy cord the first few times, but I guarantee you'll understand stalls much better after these exercises.
Let me know if you have any questions. Since I don't get to teach much anymore, I am always happy to lend a helping hand.