Sparklines from GUI is controlled by the "sparklines" X-Function, so you have to invoke LabTalk for that
wks=op.find_sheet()
col = wks._col_index('B')
col += 1#convert to LabTalk 1-offset
wks.lt_exec(f'sparklines sel:=0 c1:={col} c2:={col}')
You can find usage of an X-Function by typing into Script Window
sparklines -h
CP