Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Height
PRIM_FIGURE_HEIGHT
Parameter: Segments
PRIM_FIGURE_SUB
Parameter: Legacy Axis Mode
PRIM_FIGURE_LEGACY_AXIS_MODE
Parameter: Switch to Updated Figure
PRIM_FIGURE_SWITCH_TO_UPDATED