I can't speak to those courses you've listed Ben, but something I found out (the hard way) during our search for land at Old Barnwell, is that those USDA soil type maps aren't exactly accurate, as there's often a mix of different soils at any given place, and there's also a big difference in terms of percolation rate and erosion control between the various types of sand. I can't tell you how many times I'd look at a property based on the soil maps from MapRight, show up on property, and see nothing but standing water and red clay. Even at OB, a not insignificant amount of the site has clay deposits, sometimes with sand underneath, other times not so much.
I in now way pretend to be anything other than a poorly educated person when it comes to this stuff, so I'm sure there are others who can chime in with more knowledge. My only point is that the line of sandy soil that curves from the panhandle of Florida up through the Sand Hills of NC isn't quite as pure as, say, the soil at Sand Valley or on parts of Long Island.