The bowl pads will gradually soften as your body's natural oil greases them up. By then, the pads will exert less pressure on your ears, and the fact that they now make the drivers closer to your ears will also decrease any perceived shrillness and thus "soften" the sound somewhat.
From my experience using the SR225s, a very important thing to do is to bend the headband so they fit your head. To me, that helped increase comfort the most. Don't worry about breaking the headband, because it's very flexible. If that doesn't help, then you can try using the comfy pads. They won't sound as good as either the bowl or flat pads, but you can cut a quarter-sized hole in the center to expose the Grado drivers.
And if you still don't find the Grados comfortable, you can try going to Headphile's website and ordering some C-Pads, which greatly increases the comfort of the Grados while improving the soundstage.