If you don't mind trying another 28 mm tire, the Continental GP 4 Seasons should be grippier than Gatorskins and just as durable.

Grand Bois tires are another option, but they are rather expensive. They are about the lightest 30-32 mm tires available, and rolling resistance is supposed to be low. I just wish they were available in all black rather than just skinwalls.

http://www.vintagebicyclepress.com/Tires.html