Paths if installed once on server and shared across domains

I'm out of combinations to try in order to get the paths correct for $baseUrl and $baseDir (using php, plesk)

I have ckfinder installed once on the server outside of the root at /var/www/vhosts/foo/centralscripts/admin2/. Then each of our domains run ckeditor & ckfinder from that central location.

Specifically:
/var/www/vhosts/foo/centralscripts/admin2/ckeditor353/
/var/www/vhosts/foo/centralscripts/admin2/ckfinder/

On fckeditor 2.x, using its integrated browser the following worked:

$Config['UserFilesPath'] = '/editor_upload/' ;
$Config['UserFilesAbsolutePath'] = $_SERVER["DOCUMENT_ROOT"].'/editor_upload/' ;

In hpttd.conf, an alias is set up so that those centralscripts files are referenced/found on each website at domain.com/httpdocs/admin2/.

The uploaded files are found/saved on each domain at:
/var/www/vhosts/domain.com/httpdocs/editor_upload/File/
/var/www/vhosts/domain.com/httpdocs/editor_upload/Image/

The php page running ckeditor and ckfinder is at:
/var/www/vhosts/domain.com/httpdocs/admin2/editor/edittest.php (being called by the alias in httpd.conf)

The problem I'm running into is that the browser isn't looking on domain.com for editor_upload. It keeps looking in the centralscripts folder. All of the variations I've tried for defining paths for $baseUrl and $baseDir either result in Folder not found message or creates the new folder structure in centralscripts.

Here's what I have on my edittest.php page.

$CKEditor = new CKEditor();
$CKEditor->returnOutput = true;
$CKEditor->basePath = '/admin2/editor353/';
$CKEditor->config['width'] = 600;
$CKEditor->textareaAttributes = array("cols" => 80, "rows" => 10);
CKFinder::SetupCKEditor($CKEditor, '../ckfinder/');
$initialValue = $point_details['content'];
$code = $CKEditor->editor("content", $initialValue);
echo $code;

What do I need to change and/or define for $baseUrl and $baseDir? Thanks