I have had both for years and the only real difference I have found is that some wild caught male cherryheads were sexually mature at a fairly small size.
My two W/C males were both only 7 1/4 inches when I got them and they were quite ready to breed. But after a few years they were both 9 inchers. Smallish to be sure, but not 'dwarf'.
Also as Paul mentioned, females can get really good sized. And I have also seen long term W/C males that were well over 12 inches.
Still, I would say that the cherryheads are slightly smaller than the northern forms but not by much.