12-12 for 30 days

I have 12-12 three gdp and two gk for 26 days,goal is thirty.Plants have been outdoor all there lives.Can i cut more daylight out for 6 days or should i continue with 12-12 til the end.transplanted them into 7 gal. pots march 23rd.Trichomes starting to turn amber.Thanks Ken

i never harvest until at least 60 days of flowering