Paul -

I believe the best answer to your question starts with defining how you typically handle units within your facility.  Keep in mind also one limitation of 500:  you mentioned Raw Materials and a key if you are using the Manufacturing module of 500 is that the manufacturing module does not allow you to issue or produce in any unit of measure other than your stocking unit of measure.  This means that if you stock your items with a unit of measure of feet, but you issue the same items typically as an "each" for a work order then you are going to have to manually do this conversion as you enter each manufacturing transaction.

Once you clearly have your stocking unit of measures defined for each item you can then work on the conversions to other stocking units of measure.  I have had clients that have utilized PACK or CASE as well as other Units of Measure that can vary based on the item.  This means defining an override to the unit of measure a the item level.  I have found that many clients often find it helpful to instead of defining these generically as PACK or CASE and then having to define at the item level the actual conversion factor to do it by building this into the Unit of Measure.  For instance CASE8 is a case of 8 Each and CASE12 is a case of 12 Each.  Then assign the right specific CASE UOM to each item.  This makes it very clear when someone is working with the item to know what the correct case count is for each item.

Hope that helps!

Russ answered most of the big things about picking the Base per Unit or Unit Per Base. One other is we just figured people would want to see things the way they normally do, so if EACH is your Base and Cans is a related UOM, then you'd probably want units per base (say 6 or 12), rather than being forced to specify0.16667 (as one example)