RBM33G and 2 R11e-2HPnD card setup

Is there anything special that needs to done with a 2 radio setup using R11E-2HPnD cards such as modifying polarity of antennas? Each card has two antennas.

If I have e.g. 4 SSIDs is it best to put 2 on each radio or is putting all 4 on each radio ok?

What are the benefits beside throughput having 2 radios?