Aren't there are only Seven different Rings (x2) that you need for all Classes?
As a lot of classes share them
Heal, Cast, Dexterity, Strength, Vitality, Gathering and Crafting
If you have all your classes at one level (eg: 60), then you would only require 14 Ring slots altogether
Weapons/Tools on the other hand need priority for more space as with all Classes that comes to 24 (23 slots and 1 equipped), only 2 slots left