To be frank, I don’t really understand the question but…
There is a simple way to get the angle between any 2 vectors:
Angle = Acos(DotProduct(V1,V2)/(V1.Size()*V2.Size()))
If both V1 and V2 are normalized ( V1.Size() = V2.Size() = 1.0f ) the angle simplifies to:
Angle = Acos(DotProduct(V1,V2))
Don’t be afraid of angles fluctuating. Angle values always flip their sign at the end of the circle the same way you go from 0 to 180 degrees then flip to -180 and back to 0.
Be careful of what Acos() returns (degrees or radians).