Great Add-on. I'm using two instances using the following configuration;
#redis cache
$config['cache']['enabled'] = true;
$config['cache']['provider'] = 'Redis';
$config['cache']['config'] = [
        'host' => '127.0.0.1',
	'port' => 6379,
        'database' => 0,
        ];
#redis guest cache
$config['pageCache']['enabled'] = true;
$config['cache']['context']['page']['provider'] = 'Redis';
$config['cache']['context']['page']['config'] = [
        'host' => '127.0.0.1',
	'port' => 6380,
        'database' => 0,
       ];
}
If you want to do the same -> 
https://gist.github.com/akhdaniel/04e4bb2df76ef534b0cb982c1dc6225b
Thanks!