I have not tried the turbo fins yet because of the 10th gear description I've read in reviews. My main sport is cycling and from that I know a faster (low resistance) pace is more efficient and less tiring than a slow (high resistance)pace. This is very effective in cycling especially for long distances, and I assume the same for the Hobie Mirage drive.
As a cyclist, you should be able to run the Turbofins easily at 60 to 65 CPM for extended periods (once you get used to them). It doesn't feel as you might imagine, since you're pedaling in a fluid medium rather than a hard and fast gear. So there is always some "give". At that speed, I think of the resistance as what you might get on a gentle hill -- there is still room for acceleration (you're not maxed out at all).
Aside from the size increase, the Turbofin design is more efficient than the standard fins for several reasons. So at the higher boat speeds the Turbos are still driving whereas the standard fins are starting to "feather" out. I think this more than compensates for any loss in leg efficiency due to slower CPMs.
For touring, this will dramatically increase your range; your biggest problem will be what to do with your extra time while waiting for everyone else to catch up!
Did I mention acceleration? If you need to, you can really "grip" the water with these babies -- useful in a variety of situations like the one below:
Perhaps these non Turbo models would be the best of both worlds for you, but between Turbos and standards, I think you would be very comfortable with the feel and performance of the Turbos.