Mike:
We do the final float of ALL of our own greens [including remodels], and we probe them relentlessly to make sure we've got them right. [I wish our roles were reversed here, as I'm sure you would have come up with a terrific analogy for how much probing the boys do; I wasn't even going to try to compete with the master there.
]
Phil:
The USGA Green Construction method was developed in the 1960's. Basically, it is a system where the green is built in three parallel layers
1) a subgrade of native soil with herringbone drainage cut into it,
2) a 4-inch layer of fine pea gravel, and
3) a 12-inch layer of specially approved sand/peat greens mix.
The whole premise of the system is that the layers create a perched water table, where the water held in the greens mix layer does not flush down into the drainage until it is saturated. I have never been entirely sure WHY you would want to do that, and I've always suspected the real reason they came up with the system had more to do with enabling construction without compaction and establishing a standard for the greens mix itself. But, the perched water table will only work if the layers are all at a precise uniform depth, and even then there is some question whether the hydraulics really work as they are supposed to work theoretically, when you are dealing with a heavily contoured surface instead of three flat layers in a box.
A "California green" doesn't have the layer of pea gravel to perch the water table, and is generally 100% sand instead of a sand/peat mix.
A "push-up green" is generally built with native soils or with sand piled up on top of the native grade, rather than dug down into a subgrade.