I usually commute in casual clothes- no one at Georgetown would be caught dead wearing their biking clothes, well maybe if it was very expensive and said hincapie on it or Gucci or....

I use the Terry Liberator X also. I feel the sit bone pressure for the first few days of riding and then I either become null to the pain or it actually goes away. Either way I'm not feeling it. Also I avoid taking a load on my back. I'm on a touring bike and so it may be less upright than yours, however.