GaruuSpike 
Emotional support birb
I don't think minute changes in wing angles are done with any math calculations; I'm fairly certain it's more of a tactile, instinctual thing. Gallus knows exactly how to angle his wings in response to how strong the air current **feels** on him, much like how humans know exactly how to keep their balance at all times assuming that nothing unexpected and external happens, such as them being bumped/tripped/caught on something, and even then, humans are very good at recovering their balance if it is upset