The Mega Tree kit came with the AlphaPix Evolution CPU and the Flex 16 SPI expansion board. There CPU board can connect up to two more expansions, for a total of 48 outputs, however the CG-1500 enclosure is only tall enough for 1 more expansion.
Each of the 16 strands on the mega tree, uses up one output, which is fine, as I don't intend to use this for anything but the mega tree. Will most likely go with a Falcon controller for other things in the future. The AlphaPix works just fine, but the interface for example, is way dated compared to Falcons.