What are the best practices to track inventory for multiple pack sizes of same raw material item?

Summary:

For a raw material item we have scenarios where they are sent in different pack sizes sometimes by same supplier or different supplier. For example, even though we set 1 CASE = 50 LB for the item, there are sometimes situations when they are sent in 55 LB and 60 LB packs.

We want to understand that what are the best practices in tracking such different pack sizes. As inventory in Manage Item Quantities gets tracked only in Primary UOM or in Secondary UOM, even if we create different UOMs for this scenario, how could we track inventory in each UOM through any data models or otherwise?