John, thank you for a great article.
I do have a related question - maybe you can point me it the right direction. For internal DNS we sync our GTMs' DNS Express with AD Integrated DNS that is managed by another team. By default, CNAMES that point to the names of servers in AWS are not being resolved to an IP by DNS Express (in contrast to the behavior of the AD integrated DNS). Would there be some way to allow these to be resolved, besides using Irules or Wide IPs? (Thinking along the lines of some Notify Action setting or an unhandled query action) I am looking for something that would not require us to touch DNS entries after they are added to AD integrated DNS by the server team, but still be able to use the great performance boost of DNS Express.