Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Radius
PRIM_SPHERE_RADParameter: Segments
PRIM_SPHERE_SUBParameter: Type
PRIM_SPHERE_TYPEParameter: Render Perfect
PRIM_SPHERE_PERFECTParameter: Switch to Updated Sphere
PRIM_SPHERE_SWITCH_TO_UPDATED