Here is the way we do it currently, as posted by Greg:
(from bottom up);
PVC spacers (size determined by desired depth, determined by preference with certain tanks), Egg Crate, #7 mesh (needle point), LECA (about a 2 inch layer), and then New Zealand Sphagnum moss
Plants are planted directly into the LECA, with or without some sphagnum wrapped around their roots - depending on the plant. Most are planted directly into the LECA.
We do not use the sloping bottom false bottoms anymore either - except in larger tanks where we circulate the water with a pump. Therefore, we take a length of pvc, notch the bottom end and stick it down one corner of the tank
- so we can siphon out water when it begins to reach the egg crate. Drilled bottoms with bulk heads can replace them. Also, if you want to hide the pvc better (in the corner you need to plug with a foam plug, but the frogs like to sit on them) you can punch it though somewhere out in the tank space more and put a clay pot over it - which the frogs like to sit on too, and springtails like to come out and graze on the algae that grows on them.
Lastly, some people have complained that the false bottom setups are unsightly and look unnatural (yeah, cause it's a TERRARIUM!!)

. Well, I go for what works best rather than looks unnatural, but that is my choice. However, if you actually don't enjoy seeing how the root systems develop, then use black silicone on the inside glass up to where ever you want, or spray paint the outside glass - prior to setup.
Lastly, for years I struggled with the dang PVC spacers moving around under the egg crate. Some people solved this by siliconing them in, but I find it frustrating when tearing down a tank to have to scrape the silicone off. I take a drill and drill to holes near the tops of the spacer, then secure it to the egg crate using zip ties. You can leave the excess ties on, as they become very helpful when placing or removing the false bottoms.
Thanks