they only place on top for even metas, only on bottom for odd metas

additionally, they won't make a full slab

Bleh, freakin nibbles. We will probably need to break up the slabs into two groups like the logs and stairs. Minecraft probably uses the meta data to determine where to place the block in the blockspace and I'm using the whole nibble for the color channel.

yep. :/ Since we need a top bit (usually 0x8).