Be careful when you talk about processors with regards to the V-Ray licence. You need a V-Ray licence for each occupied socket. If you have one socket occupied by a chip with 4 processors, you only need 1 V-Ray licence, not 4.
You would go for a V-Ray licence if you need a lot of Agent for Applications and Databases licences to backup things, like SQL Server, Exchange, etc. These licences come free with the V-Ray edition whereas if you buy a hypervisor licence for the host, you need to pay for these licences. You got to do your sums to see which one is more advantageous. Offhand, in your case, I think it might be cheaper to buy 1 hypervisor licence and the necessary Agent for Applications and Databases licences.
