Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Lock On Select
HAIR_TOOL_BRUSH_LOCKParameter: Selected Only
HAIR_TOOL_BRUSH_SELECTEDParameter: Hair IK
HAIR_TOOL_BRUSH_IKParameter: Collisions
HAIR_TOOL_BRUSH_COLLISIONSParameter: Coll. Radius
HAIR_TOOL_BRUSH_RADIUSParameter: Mode
HAIR_TOOL_BRUSH_TYPEParameter: Falloff
HAIR_TOOL_BRUSH_FALLOFFParameter: Strength
HAIR_TOOL_BRUSH_STRENGTHParameter: Width
HAIR_TOOL_BRUSH_WIDTHParameter: Falloff
HAIR_TOOL_BRUSH_FALLOFF_CURVEParameter: Distance Falloff
HAIR_TOOL_BRUSH_DISTANCE_FADEParameter: Distance
HAIR_TOOL_BRUSH_DISTANCEParameter: Falloff
HAIR_TOOL_BRUSH_DISTANCE_CURVEParameter: Viewing Angle
HAIR_TOOL_BRUSH_VIEW_FALLOFFParameter: Falloff
HAIR_TOOL_BRUSH_VIEW_FALLOFF_CURVEParameter: Guide Falloff
HAIR_TOOL_BRUSH_GUIDE_FALLOFFParameter: Falloff
HAIR_TOOL_BRUSH_GUIDE_FALLOFF_CURVE