No books needed
The speed of rotation and the angle relative to direction of spin - control the ease of exit
I can spin from as high as I like and still stop a spin in 1/2 a rotation
HOW?
practice aileron and elevator and rudder settings -change em one at a time till yo u see how it affects speed of rotation and angle of fuselage during rotation.
General rule - the flatter the angle - the slower the rotation
has to do with conservation of angular momentum - -like an ice skater hugging body or extending arms .
The steeper the angle of the fuselage - the more easily the model will assume flying speed when commaded to stop the rotation.
The flatter the angle of the fuselage - the slower the rotation - so set throws till yo u get the happy combo you want
The cg will affect BOTH of these conditions
An extremely light model will stop fastest - because it resumes flying attitude at a lower speed.
My really light stuff can be controlled to 1.2 turn with ease- just relaxing controls
Inverted spins have the advantage of the fin n rudder being a "sub fin"- relative to direction .
easier to stop the spin.
Cessnas etc., I have no experience with doing spins - not my interest ..