I'm not sure how this would work. From reading the documentatioin, if I set it as a 'price per product', then I have to add a shipping price to each and every product.
You will get a "Price per product" option on that same screen where you will be able to configure a fixed shipping price for each product added to the cart which will be summed up and added to the main price of the shipping method.
If you have activated the "HikaShop Shipping manual - Prices per product" plugin via the plugin manager of Joomla, you will be able to configure prices for that shipping method for each one of your products on their edition page
However, they are using a manual shipping method that applies a fixed shipping cost based on the sum of all products put into the cart. So the 'price per product' is not a solution to our problem.
I noticed that on the product page, there is an option for "Product tax category" which could be set to 'None'. Why not simply have a "Product Shipping Category" with the same ability to set to 'None'.
Also, on the manual shipping, there is a 'Warehouse' field, yet I cannot find that field on the category or product page. It appears this has not been added yet. If we had this added, we could simply have a 'Free' warehouse and problem solved!
Warehouse : You can restrict the shipping method on a warehouse, the warehouse management will coming in a future release of HikaShop.
So I kept playing around with this and found a solution. I set the weight on the product to '2 lbs' and put a restriction on the 'Free Shipping' shipping record for '1 lb' to '3 lbs' and set that as the first record. It works. As we are not using weight at all, this works for us at the moment but if, at some later time, we need to use 'weights' then we'll still need another way to not charge shipping for certain products. I still think a simply 'Charge Shipping (Y,N)' on the product and characteristic records is the best way to do this.