Pre load is not the thing to adjust to get a plusher ride. Pre load is used to get the suspension to work over its full range. Turn the pre load down all the way and you'll likely get bottoming when the suspension runs out of travel, and turn it up all the way and you'll likely getting topping, when the suspension decompresses and hits the limits of full extension. The net is you want to set your pre load up so when you're on your bike all geared up with your feet off the ground you get about an 1 to 1.2 inches of sag front and rear on a streetbike.
To soften your suspension up, you typically want to reduce the amount of compression damping. This will make the suspension more compliant to hits. With respect to rebound damping, if you soften rebound damping up you'll get a looser ride as the suspension will rebound from compression faster. Too much rebound damping and your suspension may not rebound enough between hits and pack down, which will result in a very harsh ride.
Two good articles to read are
Sportrider Magazine's suspension setup guide and their
troubleshooting guide.
The first sentence of the second paragraph in their setup guide reflects why asking folks on a forum what their settings are is not a good approach:
"One common misconception is that there is some magical setting that will work for every rider in every situation (and we'll be the first to admit that our suggested settings are not that wonderful setup, but rather a starting point)."