RAC 11gR2 and OS upgrade

RAC 11.2.0.3.5 on RHEL 5.7 with RHEL kernel CVE-2012-1675/COST workaround implemented (SSL communication between listeners and instances)

The customer wants to upgrade the OS and the HW. The idea is to add new nodes and remove the current ones.
Oracle says it could be done (RAC: Frequently Asked Questions (Doc ID 220970.1), Does Oracle support rolling upgrades in a cluster?). I'm considering the following guide:

How to Add Node Instance or Remove Node Instance in 10gR2, 11gR1 and 11gR2 Oracle Clusterware and RAC (Doc ID 1332451.1) (which actually points to the official documentation).

I should add the COST workaround and, I suppose, a relink of the binaries? Real world experience, suggestions or gotchas are welcome.

Thanks
Dimitre

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