Dual Unit of measure

Hi,

I'm investigating on the set up of dual unit of measure. I'm working on the paper industry and I have to set up the following modules: Sales order Management, Transportation, Purchase order (with cycle routing), Process Manufacturing.

For this Company the price and cost have been defined based on EUR/TON and the transactions have been entered based on EACH.

I'm performing some tests in order to verify the transactions, the availability and commitment, but I'm wondering if there is a particular consideration that I should do in order to understand which primary unit of measure I should use.