Something that is not very clear for me on a first read:

do you have one configuration table for all the environments or has each environment its own config table?

If it is the latter one, why use a .dtsconfig file?

In my set-up (each environment has its own config table), the environment variable points directly to the config table.

Another question: why don't you store the packages in the MSDB folder? Do you have specific reasons to do that?

And to end my reply: I think a nice addition to the article is an explanation on how to configure your packages using the configuration table. E.g. using the package configuration wizard in BIDS (of which you have 1 screenshot).