Pattern boards and pantographs are used from the back side of the long arm machine. Pantographs are "traced" by using a laser pointer. Pantographs are only guides to maintain basic shapes and proportions while the operator has total control of machine movement.
For more exacting patterns, I use pattern boards. The stylus guides the sewing machine and keeps the stitching within close tolerances.
Both of these methods require the operator to stand at the rear of the machine and watch the patterns rather than the actual sewing on the quilt top. This is why framing or basting the edges of the quilt top are very important to minimize problems when beginning a new row of stitching.
When quilting "free-hand" designs, I use the front handles (left side of picture) and watch the actual sewing on the quilt top.

In the coming year, I plan to add a computer controlled machine carriage. This will allow creating custom proportioned patterns to precisely match the design and piecing of the quilt top.