Any sturdy work surface will suffice as a benchtop to mount the H-Series machine. You can find the mounting hole dimensions here, and generally use the bolts that the machine were shipped with. If longer bolts are required, the thread is M8x1.25mm.
For a custom bench, the two files below show the workbench design that we used for the H3 prototype machines. It is a simple design with aluminum extrusion corners, ½” and ¾” black melamine panels, and penetrations for mounting screws and maintenance access. For the Hybrid machine, we used this same design, but added a ¼” steel plate to the top for added stiffness. We will provide a more fully-developed design as the delivery date for the early adopter machines approaches.