Separate script files may share the same SignedUninstallerDir setting. By setting up a common directory to hold signed uninstaller files, you won't have to re-sign the uninstaller each time you compile a new script file with a distinct OutputDir setting.
If SignedUninstallerDir is not a fully-qualified pathname, it will be treated as being relative to SourceDir. Setting SignedUninstallerDir to . will result in the files being placed in the source directory.