It could just be a different phenotype. Breeders try to stabilize their strains so it comes out mostly the same, but you still get slightly different plants from the same mother. It's nature's way of covering all the angles. Your ww2 on the right looks like it has the most sativa in it of the 3 plants to my eye.
10 inches is pretty good but the closer you can get it without burning, the better. I read someone's post, maybe in the 150w club whatever board that's on, where they said their cooltube was cool to the touch and the plants could get right up in there. I've never had a cooltube so what do I know? Whatever works for you, obviously you're doing well already.
PS. Ecotec with Wai, bored out TB, 2.4 intake manifold, tsudo 4-2-1 long header, 2.5" exhaust, Dynomax muffler. Named my car Screamin' Mimi.