Victor Sellés Guillemat found out that in some countries, Google has implemented advanced functionality in Google Merchant Center that simplifies shipping settings.
All you have to do is add the address of the warehouse from which the orders leave and the preparation time and Google will calculate the delivery time.
The screenshot accompanying this post shows the shipping setup for Germany, but it may work in more countries where the following carriers are used: FedEx, USPS to UPS
