I'm not an expert on any of this, although I've done my fair share of research. But I don't think it would matter either way, until september would probably save you an extra trip to the barber. Also I've read you can get away with 3/4in but 1in would be safer unless they specify having atleast 1.5. I going with 3/4" (I also am in a similar situation) because my last sesh was 7/11 and and my test will be between 8/1 or 8/5. I have a thread if you want to check it out but no one will help lol (what are my chances).