Hi there, just installed Sendy yesterday. Everything went smooth except for me missing both your note and amazon's note about SNS region for the feedback setup. How did I manage to miss both notes!? They really stand out now I see them of course.
I'm up and running completely on amazon using a T1.Micro EC2 instance to host both the web app and the sql server. One thing that would be handy is a walkthough for getting sendy installed on EC2. I know little at all about linux but managed it following a wordpress walkthrough.
The longest part of the process was mostly waiting for amazon and DNS servers.