I agree with a lower tire pressure. A heavier person does not need higher pressure, they need a wider tire, either 25 or 28 would work in your case. A tire needs to bounce on the road, what I mean by that, the sidewalls need to flex when you go over bumps. With a higher pressure, the sidewalls can't flex. If the sidewalls don't flex then the wheel takes the brunt of the bumps, potholes, and undulations in the road and your wheel life will be shortened. Manufacturers design tires and bikes to have a 15% tire drop, means when the rider sits on the tire, the tire will drop or squash 15%. If it doesn't, you either need to adjust the tire pressure or the width of the tire.