You don't really need or want to bury any LR in the substrate, as the "live" part that gets burried, will be dead, as coraline is not going grow below the substrate line. And since LR is expense, why bury any of it in the substrate? Instead, lay your foundation with base rock, which is dead, on the floor of the tank. Fill the areas around the base rock with all LS or sand that is seeded with LS, this will be around 5" of sand. Then, build the rest of your rock structure with the LR on top of the base rock, and above the substrate line. Any exposed base rock will then become "live" as the algae and micro-organism on LR will spread to the dead rock.
You can go substrateless, however, this is not as visually appealing. If you are going to fill up your tank with mostly rock, then this won't matter as much as you won't have much floor space anyway. Algae will eventually cover the floor of a substrateless tank; this type of setup is also a lot easier to clean.
Using a deep sand bed [DBS], you will need what is referred to as "detrivore kits" which is basically substrate burrowing creatures that sift thru the sand and eat the debris within the stand. This site refers to these "kits" as "cleanup crews".
Be sure you have enough lighting to support LR, otherwise, your investment will be for naught!
[ May 26, 2001: Message edited by: Beth ]