^^ what she said

I top the taller, more vigorously growing plants and allow the smaller plants to grow naturally. That helps to keep the canopy relatively even, but of course no canopy will ever be perfectly even, unless like you said they are all clones of exact same age and condition. This is easier said than done because not all of your clones will root at the exact same time.

I don't train tops unless a plant just gets too tall on me during flowering when it's too late to top it again. For me, training is just a hassle that I rather not be bothered with.