The -1.3 to -1.8 for the rear camber is the standard (non-sport) alignment value. The "sport" settings (which is what you car orginally came with) are indeed -1.8 to -2.3. Similarly for the front camber, the standard range is -0.7 to 0 while the sport range is -0.4 to -1.1. Bear in mind though that those settings are for the car in the specified load condition. Without the weights the front camber reading will change a little and the rear camber reading will change a lot even with no actual physical changes to the setting.
In regards to tire wear, is the toe setting that really determines the overall rate of tire wear while the camber only influences location. To put it another way, you can run a heck of a lot camber and not worry about the tires wearing funny so long as you've got the toe set correctly.