Molly, I have tried both ways on the Knock Out roses. My "unpruned for 8 years straight" group is about 5' tall, and they are bushy, not leggy. They bloom from top to bottom. Others that I have pruned down to 8" grew well, with the only difference being that they were only 4' tall at the end of the summer. I'm in zone 6/7, though, and have extreme heat and cold so my experience is very different from Florida. I grow all the Knock Out varieties, and for me, they bloom from April until November with no fertilizing, no pruning, no additional irrigation. I talk to them, and that's the care they get.
Having said that, I know how huge the KOs get in warmer zones, so you could still prune them now, slow down that growth and maybe prevent that legginess you see.
Your others look great!
