Just because the 60-70 is most popular means nothing.It is what can you comfortably pull when it is cold outside.You can get it done with much less than 70.I hunted last year at 53#'s because of a bad shoulder and killed a great buck.I am back up to my normal 58# this year.
My daughter will be using 36#'s and my son will be using 40#'s.