Hi Bill,
Wow, it's almost been a year since I was experimenting with LEAP and a hat-based HMD rig. I'm out of touch with the specific versions of the development kit available now.
However, what I recall is that the "old" version was intended for placing the device on a tabletop, whereas the Orion version was intended for an HMD. I found the tracking to be much better in Orion. Therefore, since I didn't have a VR system available, I attached it to a hat to simulate the HMD placement.
LEAP also provided specific files for Unity projects, which should help you get started quickly.
John