I disagree that there is no "right hybrid" for those conditions. The right hybrid for those conditions is the one that has the best mileage when driven in those conditions. Though I haven't done any experiments, I would expect the '06 Civic to be best under those conditions for the following reasons:

At very fast speeds, almost all the work involved in driving is overcoming drag. Also, since that sort of driving is steady load for the most part, the electric drivetrain itself isn't as much of a factor as other conditions. The efficiency of the ICE itself is more important as a result.

The Civic has an excellent engine, with a lot of work done on reducing internal friction, which matters when revving higher for long period of time. It also has a very streamlined body. As a result, I would expect it to do best driving at fast highway speeds (read 75mph+) compared to other hybrids, though closest to the Prius which is also very streamlined.

The next most significant load when driving fast is rolling resistance. Pumping up the tires a bit to a level that is still safely within the max sidewall of the tires, but higher than the stock level (which seems mushy and underinflated to me anyway) should make a bigger difference at those fast highway speeds than in other driving conditions as well.

For longer road trips where I drive 75-80 in my '03 Civic Hybrid, I've managed to average in the mid 40s. Driving 60mph yields about 60mpg. This means each hour saved by going 75-80 vs 60 costs about $3.50 in fuel at $2.25 gasoline. As a result, on daily commutes I just go with the flow in the middle lanes. That could be anywhere from 65 to 75 mph. For long trips though, I just pay the price and drive faster, rather than spend so much of the day driving.