Centera Virtual Archive or add new Centera Cluster

I'm working with a customer who has two centera clusters, one in one data center (DC1)  and another in a separate data center (DC2).  The centera at DC1 replicates to the Centera at DC2.  The Centera at DC1 is maxed out and the one at DC2 is two cubes short of being maxed out.

It seems there is not a lot of detailed information on Centera Virtual Archive that I can find so the questions I have are:

The EMC Centera Virtual Archive Planning and Configuration Guide says that if you configure add Centera Virtual Archive at the primary site and are replicating then you will need to configure a Centera Virtual Archive at the target site.

Question 1 - In my case would I need to add a new centera cluster at DC2 and configure it as a Centera Virtual Archive so I can configure replicate DC1 and DC2?

Question 2 -  Is the only real benefit to the Centera Virtual Archive is not having to change application settings to point to a new Centera Cluster?

Question 3 - How much down time is required to configure a Centera Virtual Archive?

Any other input on the pros and cons of configuring Centera Virtual Archive vs just standing up two new Centera clusters would be VERY helpful

Thanks in advance