The way that you are adding in the zone values for the items you will not be able to add individual values for the various options. It will need to be done on a per item basis.
To create the shipping zone charges you will just use the subtotal of the zone columns. For zone 1 shipping you will use the subtotal of the zone 1 column, then for zone 2 use the subtotal of the zone 2 column.
You will need to determine what zone the items are being shipped to, then based on this you will trigger one of the charge rules versus the other. How you determine what zone to send to based on the user input information will be a custom part of this that you will have to come up with.
When you are testing an update recordset you will need to make use of the filtered variable in order for the recordset to return any results. The rs on the update page is filtered for the specific item based on it's id.