Here is my recommended mounting method for training gear.
Note how the training gear is mounted so that the helicopter is raised up off of the flight deck. The Helicopter skids to not ride on the ground but the training balls do. Training gear can go under or on top of the skids (as shown) but must be tie wrapped in such a way that the training gear is not sliding around in the skids or else the helicopter can tip over if they slip and slide. this also assures the center of gravity is maintained best with the center of the training gear as close to the bottom of the mainshaft. Note that you will want to periodically rotate the balls on the rods to keep the wear on the balls even and not develop holes. These inexpensive training gears will affect the balance of the helicopter much less than the older method of using long wooden dowel rods and wiffle balls.
