I don't think nit is a good idea to trim at this stage...You are too far into flower and trimming could hermie the "lot" of them.
Get a string trellis at the garden store, and put it over top of them and tie down, or do what I used to do, before I got my grows under control. use big "Nuts"...like nuts and bolts, "Nuts"...and use a twist tie to attach the nut to the top of the plant to weigh it down...Works great, If the top is weighted down your under branches will fatten considerably, good luck.