Thanks for the benchwork insight. I'll keep it in mind with my discussions with the guys at Mianne. The Mianne guy also told me that since Dad wants a bit of space to sit next to the layout that we may incorporate a type of cantilevered design to prevent the plywood from warping over time. I do like the fascia that is on the layout. I'll see if Dad wants that. We have a bunch of 3/4 inch plywood from Dad's old layout that we can reuse.
The Scottish Kelpie is a creepy one.... I have never heard that one before. Kelpie is a name my wife thought up because I like to mess with kelp that washes up on the beach. Of course, Kelpieflyer can also refer to a Scottish Pegasus or maybe a flying fish or Screeching Eels from Princess Bride?
Since you have the 3/4" ply to use, it shouldn't need any support. I would venture to say that you could go a foot on the overhang and still stand on it. Perhaps a support would be needed because of the minimal fastening at the leg tops only. Like Dave, I would be interested in their idea. Some locking triangles on pins would do it.
Phew! Glad to hear it wasn't a reference to mythical beasts.
Screeching Eels! Inconceivable!