After d/l the Ozone 5 and re-reinstalling, AND TAKING NOTE of the VST folders it was being dropped into, I needed to re-order my VST Folders somewhat and then re-rescan my VST Folders in SF10 and Ozone 5 appeared.
NB: Ozone 5 was apparent in the x86 Vstplugins prior to my activity today. So I did have the 32bit version installed. I can only surmise that it was my re-ordering of my Vst Folders AND the re-reinstalling that shook the tree.