Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Source
FIELDLAYER_COLORIZE_SOURCE
Parameter: Mode
FIELDLAYER_COLORIZE_MODE
Parameter: Base Color
FIELDLAYER_COLORIZE_COLORBASE
Parameter: Base Density
FIELDLAYER_COLORIZE_COLORBASE_DENSITY
Parameter: Top Color
FIELDLAYER_COLORIZE_COLORTOP
Parameter: Top Density
FIELDLAYER_COLORIZE_COLORTOP_DENSITY
Parameter: Ink Types
FIELDLAYER_COLORIZE_COLORTOP_MODE
Parameter: Value as Alpha
FIELDLAYER_COLORIZE_CLIP