Part of why I prefer to use autostick in my Special is the extra long second gear. The computer holds it, so driving around town I'll use autostick to shift up into 3rd faster. On the highway it doesn't matter, unless crawling along in a traffic jam.
And I've noticed the sweet spot is about 65mph, as I get my bet MPG there. I tend to stay around 75. In my Jeep, I gave up and typically do 80 (following the flow of traffic!). I'm lucky to get 14.5 if I hypermile it.