It depends on your weight, but if you have a 200lb load on your bike with 32mm tires, you should have
65-70psi pavement, and
45-55 gravel.

The hyper has really, really low rolling resistance, even in large sizes. It doesn't have near the puncture resistance of the 4 Season though, so be careful there. I got some 32mm 4 seasons (hard to find) and they are so, so much better than the 28mm size. The 28's run small, so there is a huge difference in size. How do you like the new tires?

People have figured out that with a good tire like that, you can go really low without much decrease in rolling resistance. There is about a 2-3 watt difference between 60-90 psi, and maybe only 4 additional watts at 45psi. Really, at 45 psi, you are only talking about 22 watts resistance, and that is incredible - I would wager that is less than 90% of the tires people are using on the commuting forum, at any pressure.

And, here is a pretty chart for ya from the tire pressure experts at Bicycle Quarterly: