This is a little time consuming, but you only need to do this once. For any other class you create you simply click on the Import button and choose an already existing class to import from. The next screen will be the continuation of the Grading Scale. Finish typing the numbers, then click the Next button. The next screen asks you the option of entering categories and which method of scoring you want to choose.
Weighted categories works well for some.
I do recommend using categories. This enables you to do a better job in tracking where a student is having trouble. It also lets the parents know when you send a progress report home that is printed by categories. Again, you may notice an Import button on the right side of the screen. If you use the same categories for more than on class, you can simply use the import feature and not have to re-type information.