many ways to skin a mule, but few optimal ways .
Quoted for truth . Your plants look very healthy and happy, no reason to think they couldn't handle being topped without skipping a beat. I'm personally against topping, unless i'm making a mother . Probably just a lil jaded from the crazy clown pounding "NO STRESS" into my head for many years. Lots of people do it and it works well for their situation. That said and from what I can see, it looks like you have plenty of vertical space to work with. You've also got alot of open parts in that screen, instead of taking away plant matter, move it so it grows to fill those empty spaces . Remember the goal is to cover every inch of lit space for max yields.