Patrick,
I'll take a stab.
Greens within a green is great. But it is possible to simply do a small green, provided all the green space is cuppable. Most supers will tell you it takes 21 days for the three foot diameter circle around a cup cut to recover. If they change pins using a 2 X 3 tic - tac - toe board system, you have six sections, with four pins 6 foot diameter pin settings each - or 24 settings, just over the necessary limit of 21.
You have 4 X 6 six foot circles, or a green size of 24 X 36. Even after allowing another 12 feet around the perimeter, to keep pins the legal minimum from the edge, and allow for a small collar, the absolute minimum green size to get required pin positions is 48 X 60 feet, or about 3000 sq. ft., small enough to test any shot. According to the USGA slope rating, this size should test an iron shot about 100-120 yards for most players. Especially if elevated to reject missed shots.
Maintenance caveats include having good growing conditions, like sunlight, air circulation, and dispersed walk ons. Also, the entire green should be under 3% slope (perhaps less on fast greens, and perhaps less if we want the golfer to provide maximum spin)
I'll grant you that on high play public courses, the super may need 27 -36 pin positions, especially if in less than optimum n growing conditions. In that case, the larger, separated greens make loads of sense. They also make sense because ball mark damage, typical on short iron approach greens is a different matter than foot traffic damage.