Great answer. Extra dark will be safer during flower than extra light but either way you should be all set. I actually give my flowering plants a single 24 hour light period around week 5 of flowering when the growth slows down to give them a boost back into growth and it works great.
I am not trying to be argumentitive but if you need to stress the plants to get em to hermie you cant really say they are hermie prone because they are fems. They are hermie prone because any MJ plant is hermie prone given enough stress.
I just checked out about 10 strains at Herbies and only found 2 that were cheaper than attitude so I guess that 1/4 price of attitude is out the window.