hey Micheal, glad to see you found the thread. Can you give us a little more info on everything.
1) How many days have they been growing?
2) What strain?
3) When you say you messed up the photo period, exactly what do you mean?
4) Yes, there is a way to determine when to harvest by looking at buds. It involves about a 40x scope and looking at the trichomes. When they are all or mostly all milky I like to harvest. Many people on here wait for them to start turning amber but that gives you more of an indica stone(couch lock). If you harvest at milky then it gives you a little less. Granted, that is depending greatly on the strain as well.