Defining Organization and Assigning Organization Classifications

Hi Team,

We are using Oracle R12.2.9.

We are in a service industry (using only Non Inventory Items) and would like to setup inventory organization for operating unit.

I would like to know what is the best way to define organization:

1. Define single Organization 'A' and assign multiple Organization Classifications to same organization as:

a) Operating Unit

b) Inventory Organization

OR

2 Define separate organization for Operating unit 'A' and Inventory organization 'A_INV_ORG' and assign organization classification OU and inventory organization respectively to each organization.

Please advice.

Regards,