Custom Shipping Calculation in UberCart/Drupal

We have a Drupal website in development using UberCart. We need custom shipping method. Each product in store has a weight ranging from 4 ounces to 2.5 gallons. These weights have not yet been assigned to products but will be shortly. The client has requested shipping be set up as the following: Meaning a base price and then the incremental addition for each product after the first. Default Incremental 4, 12, 16, 17 oz. 11.50 2.50 32, 34 oz. 13.25 3.50 1, 1.1 gallon 14.00 7.50 2.5 gallon 23.50 13.50 Example 1. Customer buy a 4oz bottle and a 1 gallon bottle. The shipping would be 11.50 + 14.00 For each product they sell in one of the price categories, they first pay the default amount. Example 2: Customer buys 2 4oz bottles and 1 gallon bottle. The shipping would be 11.50 + 2.50 + 14.00 Example 3: Customer buys 2.5 gallon bottle and 2 32oz bottles. Shipping would be 23.50 + 13.25 + 3.50 In summary, the first time they purchase an item in one of the price categories, they also pay the default first. Each additional item within that price category uses the incremental amount.