Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Strength
HAIR_TOOL_CURL_STRENGTHParameter: Angle
HAIR_TOOL_CURL_ANGLEParameter: Tightness
HAIR_TOOL_CURL_TIGHTNESSParameter: X Height
HAIR_TOOL_CURL_AMP_XParameter: X Length
HAIR_TOOL_CURL_PERIOD_XParameter: Y Height
HAIR_TOOL_CURL_AMP_YParameter: Y Length
HAIR_TOOL_CURL_PERIOD_YParameter: X Curl
HAIR_TOOL_CURL_XParameter: Y Curl
HAIR_TOOL_CURL_YParameter: Strength X
HAIR_TOOL_CURL_STRENGTH_XParameter: Strength Y
HAIR_TOOL_CURL_STRENGTH_YParameter: Tighten
HAIR_TOOL_CURL_TIGHTEN