Since V1.1.0 you can also define discount rules for every variation. Therefore click on the variation in the Variations tab and scroll down to Discount Rules.
Here you can as many rules as you need, the order of the rules are important and can be easily changed via the drag icon at the right-hand side. Only the first matching rule will be executed.
Display Discount Rules Table
In the Bulk Variations options you can choose to display a table with all available discount rules to your customers.
The head title will be created from the variation description.