Red Hat :: Regarding The Specifics Of RHEL 6 Licensing?

[As RHEL licensing has changed over time, please don't attempt to answer these questions unless either you are confident of the answer, or you have recent experience with these items.]

We are virtualizing our data center. We have a total of 23 HP blade units (2-sockets each) that will have hundreds of potential RHEL 6 virtual machines running on them within VMWare. All of these VMs (Set 'X') will need to have rhn_register run on them so that patches and updates can be routinely applied. A subset of X - call it set 'A' - of these VMs will require 12x5 support (Standard Support) from Redhat. Another subset of X - call it set B - which is mutually exclusive from set A, will require 24x7 support. For any given server, we can not yet identify which will be in Set A, Set B, or just in X alone.

If we decided we had no need for phone or web support, but wanted to be able to use RHN for patches, would purchasing one Self-Support entitlement for each VM suffice? We are probably looking at the Unlimited-number-of-guest-OS subscriptions. Is there any way to purchase Premium (24x7) support for some VMs and Standard (12x5) for others? Does the count have to be decided ahead of time, or can we decide on the fly?

In other words, can we wait until a VM crashes over the weekend to call Redhat and say "We need this VM on premium support" ? The motivation for this inquiry is that we don't have the budget to put 23 blade units' worth of VMs under premium, or even standard support. I'm curious how Redhat manages this, since subscriptions are done per physical server, not per VM. (When you're dealing with the unlimited-number-of-VM pricing.)