I will need some time to think this through, do some research and then do some "proof of concept" testing.
At first glance, the most promising direction is to fully explore Redirection as you originally suggested. But combined, not in place of, the Cookie method.
Saying that, I also need to mention that Redirection is an area that I know little about, and what I do know mostly revolves around how carefully you have to be in the WordPress environment with Redirection or you get yourself in a Redirection Loop.
On the other hand, I do not feel comfortable with the Cookie feature in the plugin WITHOUT a Redirection or equivalent solution, because so many people use Caching with WordPress, and Cookies alone ends up being a feature that won't work on most people's WordPress environments, which could become a Support nightmare for me as sink the reputation of my plugin.
Further to that, as far as Caching is concerned, I have never used Caching on any of the WordPress environments that I maintain, but my experience with Raspberry Pi and a VPS environment a year or so ago have convinced me that Caching is a requirement for higher traffic WordPress sites.
All of which is to say that I will work on this issue without expecting any compensation from you. As always, I will keep you posted on my progress here.
