[Ray]

1. No holes in the bottom. You need to contain a reservoir some how. Regular, holes-in-the-bottom pots can be used, but they then have to be placed in an external reservoir.
2. The holes in the side are typically about 1.5" from the bottom, but there's no "magic" to that height. A deeper reservoir may mean less watering, but it's the top-of-the-reservoir to the top-of-the-medium distance that should be controlled, as that's what controls the overall moistuer level.
3. I have not been impressed with lava rock as a semi-hydro medium:
   1. The irregualr shape packs too tightly, restricting air flow.
   2. If you use a coarse enough size, the wicking is not all that good.
   3. Lava rock seems to accumulate minerals far more than do decent LECA's, and does not flush well.
   4. The coarse, open surface porosity leads to "bridging" water droplets, which does two things:
   1. 1. Blocks air flow.
      2. Traps minerals and concentrates them as the medium dries.