changing ur light schedule once will be ok, ive had to do it in more than one grow, i wouldnt advise doing it more than once or twice though........have ur lights on at 6pm and off at noon the following day that way ur lights are off during the afternoon when the outside temps are at their highest. and get ur osciallor on all day, ur really going to need an extractor even if it it doesnt have a carbon filter on it, it'll still draw the hot air from your grow area and vent it to an open window, this also gives your plant fresh air, lowers humidity, and reduces the chances of mold, powdery mildew and bug problem; bugs fuckin love humid environments. just keep doin what your doin buddy and when u get the cash keep adding bits of equipment to your grow, it;ll pay off in your future grows.