Dropbox Backup for database and assets

Are there any special configuration required to get both database and assets when using Dropbox backup.

My config/runway.php file shows

'dropbox' => [
            'access_token' => 'add your own token here',
            'handler'      => 'PerchDropbox_ResourceBucket',
            'handler_path' => PERCH_PATH.'/addons/apps/perch_dropbox/PerchDropbox_ResourceBucket.class.php',
        ],

My config/buckets.php folder shows

<?php
    return [
        'backup' => [
                 'type'      => 'dropbox',
                 'web_path'  => '',
                 'file_path' => 'backups',
         ],
    ]
?>    

A Database file "db_daily_201501261101.sql.gz" is backing up to the Dropbox App folder. Status Message reads "Database backed up."

However, I did set my backup plan options for both database and assets, and don't see assets copied to the Dropbox App folder.

Do I need to configure the tmp folder location with full path on the production server in config/runway.php file and have the tmp folder writable on the on the server to also grab assets to my Dropbox App backup? I'm not using Amazon S3 yet for other assets.

When I used an absolute path on my production server, and tried to Backup Now, message was "Unable create compressed file." Seems like a write access issue to perhaps incorrect folder location.