Roger that. After some investigation and experimentation, the only way to make Leap Motion hands appear in your cockpit is via FlyInside. And the only way to run FlyInside without crashing X Plane is to use an earlier version of X Plane. I tried it, and found that the hands were not very user-friendly. There was no positive indication of switch or knob interaction, and some knobs bring up a menu for digital number entry. Some have a slider that is very overreactive (a minor altimeter adjustment throws it off several hundred feet). It was also difficult to put my virtual fingers at the proper distance to activate things. So in retrospect, the Oculus controllers are ideal. Pulling the trigger and twisting the wrist actually turns the knobs, and you get haptic feedback when things are moved or changed. The only issue is locating the controller while under goggles, but I'll lanyard it around my neck.
Thanks for your input, and I hope my "test report" is beneficial to others.