6ft, or without bucket still about 5ft??!!! fuck, and 4 weeks into flowering!? i wouldn't cut them down now anymore... would be a slash into your own flash!
get 2x1 wooden battens, fix them 2 to the bucket each and give the plants a slow limbo twist by tying them zigzag to those battens. do it just after you watered the plants and do it slow, really slow. that should lower them by at least a foot if your done
oh and put something around the stem like some newspaper pages folded several times, so that the strings or whatever you gone use won't cut into the stem!!!