Might be just your terminology, but be aware changing the front pre-load only alters the height of the front of the bike, it doesn't make the front suspension softer/harder. Raising the front may give you more straight line stability (think a chopper style motorcycle as an extreme example), but like anything there is a downside in being more difficult and slower to turn into a corner.
A properly measured pre-load (rider sag) reflecting the riders weigh (both front and back) will always give the best handling result. Doing it this way also gives a rule of thumb whether the bike is sprung suitable for the riders weight. We don't need to general think about springs in a car because the car itself is so heavy. In the case of a motorcycle the rider makes up around 1/3 of the total weigh the springs have to support. No amount of adjustment will make an over/under sprung bike perform well.
Sorry to digress, back to Road 5 tires.