Here is a chart I did before I did my post on how to install a tach on your R3T. This chart is pretty darn close based on information I pulled from people about RPM vs speed. For R3T owners, unless you corrected the speedometer in Tunecu you are not actually doing 80 when your speedometer says 80. More like 76-77.
As for the RPM's on the highway...there is a little grit feeling in the handlebars at 80 and above, but not as much as I had on my 6 speed Harley. And as I recall if I wasn't pulling at least 3 grand in 6th gear the bike was a slug. Even then If I wanted to go, a downshift to 5th was a better option. That is not an issue with the Rocket at 3K.
I don't think I will argue with the engineer's on my rocket gearing. I personally find it more about the "perception" of the RPM's vs speed. Without a tach you wouldn't give it that much thought. I remember when I got my first rocket there were several time I was driving 80 and didn't realize I was in fourth. I'm sorry, but sometimes it's just all in your head.
Wanna cruise smooth, get in the cage and go...that's what I do.