Check out the chart here: Which Came First? WCG or Watchtower Bible Society?
What I had never heard before was that JW leaders may have plagiarized Hebert's writings, just as Herbert Armstrong plagiarized JW, COG7 Day, Mormon and Adventists writers.
In HWA's basement in the old walk-in safe, HWA had lots of books from the SDA's, JW's, and other Adventist groups. He had underlined passages in the books and marked them up from much use.