Ok just so you know White Widow isnt even close to the strongest strain. Its very strong yes but only at 16% THC. Im growing White Widow x Haze which is called Alaskan Ice and it has 21.49% THC. Check it out in my signature.
you dont look at hairs, you looked at the trichomes. Your hairs can change amber, pink, purple, red, blue, green or white in the first couple of weeks, and that doesnt mean your plant is done. (by the way I have seen all those colors in hairs)
If its green house and he's afraid to tell then the strain is either K Train, NL 5 Haze Mist, Lemon Skunk, Cheese, or Alaskan Ice. Im growing Alaskan Ice at the moment. Just put it in flower.
Well for one you can do anything with tops. Its not the same as a cutting. The top is just the center of a bud site that you cut to get 2 bud sites from each 1 that you cut, doubling your colas.