first time with auto flower

I've got some berry ryder,some northern lights blue and dna;s lemon ALL auto I've got them under a 430 watt hps with a humidifier small one I'm on 18\6 light cycle it's been almost 30 days from time I put them to soil so im wondering do I turn back the light to 12\12 so as to help the plants flower better or can i leave the light cylce at 18\6 and I also have a 1000 watt mh should I use it in the last few weeks of flower or now or will this 430 do the trick Ive only got six plants growing now in a 6 by 12 room 8 ft ceilings they seem to be doing good the tallest is almost 18inches