Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Scale
SCALE_SCALE
Parameter: Variation
SCALE_VAR
Parameter: X Scale
SCALE_XSCALE
Parameter: Y Scale
SCALE_YSCALE
Parameter: Z Scale
SCALE_ZSCALE
Parameter: Over Age
SCALE_OVERAGE
Parameter: Scale Gradient
SCALE_AGEGRAD
Parameter: On
IN_SCALE_ON
Parameter: Animation Time
IN_SCALE_ATIME