Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Project Onto
POINTPROJECTOR_LINKParameter: Projection Mode
POINTPROJECTOR_MODEParameter: Projection Alignment
POINTPROJECTOR_ALIGNMENTParameter: Include Hierarchy
POINTPROJECTOR_INCLUDE_HIERARCHYParameter: Offset
POINTPROJECTOR_OFFSETParameter: Strength
POINTPROJECTOR_STRENGTHParameter: Falloff
POINTPROJECTOR_FALLOFF