Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Strength
ID_MG_BASEEFFECTOR_STRENGTH
Parameter: Selection
ID_MG_BASEEFFECTOR_SELECTION
Parameter: Maximum
ID_MG_BASEEFFECTOR_MAXSTRENGTH
Parameter: Minimum
ID_MG_BASEEFFECTOR_MINSTRENGTH
Parameter: Transform Mode
ID_MG_BASEEFFECTOR_TRANSFORMMODE
Parameter: Transform Space
ID_MG_BASEEFFECTOR_SPACEMODE
Parameter: Position
ID_MG_BASEEFFECTOR_POSITION_ACTIVE
Parameter: P
ID_MG_BASEEFFECTOR_POSITION
Parameter: Rotation
ID_MG_BASEEFFECTOR_ROTATE_ACTIVE
Parameter: R
ID_MG_BASEEFFECTOR_ROTATION
Parameter: Scale
ID_MG_BASEEFFECTOR_SCALE_ACTIVE
Parameter: Uniform Scale
ID_MG_BASEEFFECTOR_UNIFORMSCALE
Parameter: Absolute Scale
ID_MG_BASEEFFECTOR_POSITIVESCALE
Parameter: Scale
ID_MG_BASEEFFECTOR_USCALE
Parameter: S
ID_MG_BASEEFFECTOR_SCALE
Parameter: Color Mode
ID_MG_BASEEFFECTOR_COLOR_MODE
Parameter: Use Alpha/Strength
ID_MG_BASEEFFECTOR_COLOR_ALPHA
Parameter: Color
ID_MG_BASEEFFECTOR_COLOR
Parameter: Blending Mode
ID_MG_BASEEFFECTOR_COLOR_BLEND
Parameter: Use Alpha/Strength
ID_MG_BASEEFFECTOR_OTHERALPHA
Parameter: Weight Transform
ID_MG_BASEEFFECTOR_WEIGHT
Parameter: U Transform
ID_MG_BASEEFFECTOR_U
Parameter: V Transform
ID_MG_BASEEFFECTOR_V
Parameter: Modify Clone
ID_MG_BASEEFFECTOR_CLONE
Parameter: Time Offset
ID_MG_BASEEFFECTOR_TIME
Parameter: Visibility
ID_MG_BASEEFFECTOR_VISIBILITY