18/6 switched to 14/10 or 16/8. If you use weaker lights(leds, cfl and small hid) then you do benefit from the extended light time. But if you use big lights (600 to1000w hid) then you at max want 18/6 for the first three weeks then switch to 14/10 or 16/8. Even though 20/4 might work I have experiened better yields and quality in the end. They are not fully ruderalis remember they have some traits of regular strains. Rest is good after a long day of sun photoperiod. Where as veg cycle doesnt matter with photos but flowering does. Just because it automatically flowers doest mean it doesnt need rest period. Had some big yields from these little plants doing just that.