Damian

For moving through from dev to test to live, use Package Configurations. I find it works best with a configuration file that you specify in your job. There's numerous resources on the web describing how to do this - here's an example.

For changing source and destination after deployment, set up package variables called @Source and @Destination (for example), and retrieve values for those variables at run time by querying your SSISDB database - you can do this with an Execute SQL task containing a query with an output parameter. You can then use the values of the variables to set the properties of the connection managers.

John