regarding the flies, either your soil is too moist -- make sure you dont overwater and let soil dry out between waterings OR the soil you picked sucks because I had the same problem with flies also my second grow and thats because my soil was really cheap and had some kind of manure in it which attracted the flies. Ever since i switched to good quality soil and mix it with perlite, i havent had 1 problem with flies.

good luck.