There was just a thread in an MVP forum about this, and if it makes you feel better few people seem to have a grasp on this, me included. These were recommended:
Microsoft SQL Server Licensing Simplified into 7 Rules
How to Ask Microsoft a SQL Server Licensing Question
http://www.brentozar.com/archive/201...sing-question/
Why Core-Based Licensing Matters for Performance Tuning
http://www.brentozar.com/archive/201...rmance-tuning/
That said, have you considered the free version, at least to start out with?