We obtained a very good shipping costs worldwide due to keep low weight. If the weight is incremented the shipping costs may not be so good. We are working with different shipping companies to solve this problem and we will notify it as soon as we can support extra copies.
The Pledge Manager is a web application that will be launched after the campaign ends. All the backers will receive an email to sign in the Pledge Manager and they will be able to configure the shipping info, addons, select the language, etc.
The shipping costs will be payd through the Pledge Manager.
If you wnat to add an addon to your pledge go to Manage my pledge and just increment your money amount as much as the cost of the addon. After the campaign ends you will be able to assign in our Pledge Manager all the money to the addons that you want.
Don't see the answer to your question? Ask the project creator directly.