Pros are racing. At 235 lbs I use 50 f and 55 rear on my 700 x 35's. Less for off road or in the wet. Tires provide comfort and grip, among other things. Do you want to feel every 1/4 " pebble? Slightly softer tires will provide more grip and traction. It is a very personal subject, experiment and take notes. Try this, when you sit on your bike, you want them to squish a bit. Not very scientific, but it works. Trying to go faster? The factory stock tires are probably not the best.