When I selected the "complete" install method the installer apparently picked the HD with the largest available space, which was my external Raid array where my project and video files are kept. Installer created a folder named "hostcs5dest" and one named "hostcs55dest" to place all the plugins.
I then simply copied the files in the ...cs5... folder into my plug-ins folder on the c: drive and all appears to be working.
I do not know why the "custom" install method did not appear to place any files in the plugin location on c: drive as I specified. I obviously didn't provide the appropriate instructions to the installer.
Having installed thousands of programs over the past 20 years I thought I would have been able to understand this one. Shows what I know!