I am assuming that if all the prices are the same that the price is on the Product and not on the Attributes ... correct?
There is a feature in the Catalog ... Option Names ... where you can add ALL of the Option Values to ALL Products that contain 1 or more Option Values for that specific Option Name ...
1 Backup your database
2 I would take the site down for maintenance until you test that this worked correctly
3 Go to Catalog ... Option Name ...
4 Find the setting for:
Add ALL Option Values to ALL products for Option Name
Update ALL existing products that have at least ONE Option Value and Add ALL Option Values in an Option Name
5 Select the Option Name for the Ring Size from the Dropdown
6 Be sure you BACKED UP YOUR DATABASE
7 Click Update
8 go review your Products to ensure the Ring Sizes look right
9 Bring the site back off of Down for Maintenance once all is working correctly