one thing I don't get about vert is the claim of more canopy surface area. seems to me as the plants grow towards the light, your surface area is diminishing.
If u'r able to pull the support system back a little, then you can maintain the depth consistent as the plants grow... and they do grow upwards more than towards the light. But I'm basing this off of a vertical SOG design... 4 vertical walls squared around a stack of lights, where the walls are movable to & fro the light stack. Only way I've seen the canopy/yield theory pan out.