Those plants look very healthy & happy from what I can see! They look to be growing in 5gal. buckets (?) and so I'd let them grow if you have the space. You should be able to pick out male preflowers earlier than the ladies, and can thin out the garden out then a good bit then...if you haven't done so already. But especially with lst and plenty of room for roots to grow, I'd try to grow some monsters and maximize the yield!

...and the runts in the middle could possibly double/triple in size during flowering, and outgrow the other 'vigorous' plants that you've been paying special attention to. I've seen it happen, and was pretty blown away.