I too cut mine back one time usually when they are about a foot tall. Does it really make a whole lot of difference in the homebrewing world, I don't know. I just do know that the subsequent shoots that come up seem to stronger and have fatter bine stalks than the earlier ones and I always get a lot of flowers on my Cascade.
My Nugget produced like gangbusters for the first five years or so but are now starting to peter out. I was going to dig it out this year, but had a few more flowers last year, so they get one more year to prove me wrong. If I get more flowers this year, maybe I can again make my wet hopped Nugget IPA.