Increase emails sending rate

I have following batch and domain throttling settings. phpList sends emails 1000/hour with these settings and want to increase it to 2000/hours. Cron job runs every 15 minutes. Please share your suggestions.

define(‘MAILQUEUE_BATCH_SIZE’, 500);
define(‘MAILQUEUE_BATCH_PERIOD’, 900);
define(‘MAILQUEUE_THROTTLE’, 1.5);
define(‘MAILQUEUE_AUTOTHROTTLE’, 0);

define(‘USE_DOMAIN_THROTTLE’, 1);
define(‘DOMAIN_BATCH_SIZE’, 10);
define(‘DOMAIN_BATCH_PERIOD’, 120);
define(‘DOMAIN_AUTO_THROTTLE’, 1);
define(‘MAX_PROCESSQUEUE_TIME’, 0);

Thanks.