use 12 hours for the most time, say flowering time is 64 days.. last week first four days 11 hours and last three days 10 hours... the plants should think that their life is coming to an end soon so they will produce bigger buds due to the pfr hormone increase thats my guess, i will try it but got like 30 days to go before i can tell you but on the other hand i got nothing to compare to .. but this is my logic.