According to Sheldon Brown's calc 90 RPM puts you at 4.9 MPH in the lowest gear of the tourer and 7.9 MPH in the lowest gear of the roadie. That's a pretty significant difference. 11 lbs up a 20% grade requires roughly 15 watts for the same speed according to http://www.noping.net/english/. Although it will take slightly more effort to get the tourer up the hill at the same speed, it allows you the possibility to comfortably ride at a slower speed.

If you are talking about a sustained 20% grade, I would say the lower gearing wins for sure.