Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Texture
SLA_FILTER_TEXTUREParameter: Hue
SLA_FILTER_HUEParameter: Saturation
SLA_FILTER_SATURATIONParameter: Lightness
SLA_FILTER_LIGHTNESSParameter: Colorize
SLA_FILTER_COLORIZEParameter: Brightness
SLA_FILTER_BRIGHNESSParameter: Contrast
SLA_FILTER_CONTRASTParameter: Gamma
SLA_FILTER_GAMMAParameter: Enable Clipping
SLA_FILTER_CLIPPINGParameter: Low Clip
SLA_FILTER_LOW_CLIPParameter: High Clip
SLA_FILTER_HIGH_CLIPParameter: Enabled
SLA_FILTER_GRADING_ENABLEDParameter: Intensity
SLA_FILTER_GRADING_INTENSITYParameter: RGB
SLA_FILTER_GRADING_CURVE_RGBParameter: R
SLA_FILTER_GRADING_CURVE_RParameter: G
SLA_FILTER_GRADING_CURVE_GParameter: B
SLA_FILTER_GRADING_CURVE_B