OP, you have to find a way to automate the mails you send out or its not worth it.
You can use that time to try other methods that can be more profitable.
I've noticed that if you use an autoresponder, it seems too much like junk to the recipient and you hardly get any conversions.
So if anyone has any ideas on how to use an autoresponder and make it look like its a manual response (maybe time delayed), it would be much appreciated.