70 psi seems high. I'm 150 lbs and run my Conti Ultra Sport II (with tubes) around 70 psi for 700x25 on the front, 75 psi on the 700x23 front. No problems, even inadvertently hitting some rough spots hard. I could run those lower.

On my hybrid I run 700x42 tires around 35-40 psi front, 40-50 rear. No problems.

If I had 700x32 tires on a road or endurance bike I'd try around 40-50 psi, at least on the front, for gravel.