Nice thread guys, guess I'll join in and make a few of my own observations. First one is, in most vertical grows you would have a single row of plants around the light with a reflective material behind them. In my opinion it would seem to me that it would reflect more lumens back than the same material on a wall reflecting back to several plants deep(I hope that makes some sense), and that would counteract the minimal lumen loss from not using a reflector. Someone made the observation that the light saturation from a vert grow would be less and I don't even know how you can come up with that. If you look at a plant from the top and then from the side, which is the larger profile? clearly it is from the side. And if the concern is the angle of the leafs, well as we all know they will turn towards any light source. I am definitely going to be a PerVert, its just a matter of deciding what will work best for me, but probably going to be an octagon with PVC. I am thinking 6 of the sides will be fixed, with 2 sides moveable for access and 4 tiers with 2 600w lights in a double cool tube. One more thought I would like to share about this type of setup, it is definitely best for a large number of smaller plants(at least the multiple tier type not single tall plants around a light) so for anyone concerned about the law should remember it is a serious federal crime to go over 99 plants. With clones and a system like this it would be easy to exceed that limit. Good luck to all and happy growing!