Hi,
The auto selection of the shipping method is done by a call to the checkCartMethods function of administrator/components/com_hikashop/classes/shipping.php when loading the cart in the getFullCart function of the administrator/components/com_hikashop/classes/cart.php file.
So you could directly change the checkCartMethods function code.
However, I would recommend either:
- creating a class override of the shipping class, extending the default class and implementing your own checkCartMethods function
- or event better, create your own hikashop plugin implementing the onAfterCartProductsLoad trigger to set the shipping id yourself in the $cart object and saving it in the database with the updateShipping function.
With the trigger solution, you'll have a more stable solution for future updates as it's not likely to change in the future.