Nice. U cut the bottom wrapping off the slabs instead of slits in it fir drainage?You can checkout my current setup in my journal. I'm using 4" cubes now, but I'm going to use 6" next time. I think I'm going to cut out 6" sections of the slab and sit the cubes down inside instead of sitting on top though. I think that will keep the rootball happy, the plant can root out of two sides of the cube instead of just the bottom, and it will lower the height of the plants a few inches.
lusid's Cave of Blunder & Husky Hut
www.rollitup.org