Seeking further historical insight on dirty_ratio for Oracle configurations

From the following PDF link, I consumed the vm.dirty_ratio=80 config with keen interest when doing research today on recommended RHEL kernel settings for Oracle deployments.

https://access.redhat.com/sites/default/files/attachments/deploying-oracle-12c-on-rhel6_1.2_1.pdf

This setting of 80 appears to be a reversal of earlier recommendations of 15 -- can only find historically linked from URL below...
http://www.slideshare.net/ftmiranda/oracle-11gr2-onrhel60-document-from-red-hat-inc

Its not my purpose to try and lay blame anywhere for this reversal. At the end of the day, most of us involved in performance tuning understand full well that each workload should be tuned independently. Yet, we all seek a general best practice for "out of the box builds" to meet time pressures, etc.

In fact, in my experience with dirty_ratio, I have found in a non-DB environment with heavy I/O (roughly equal on read and write rates), that the higher settings of dirty_ratio results in less time spent on processes blocked on I/O. So, in short, the 80 setting is more consistent with my direct experience. But my direct experience is outside of Oracle.

Nevertheless, I must convince others of the general need to now adopt this reversal. In short, I am looking to have someone confirm the reversal, comment on any test data supporting this change, and then advise/clarify whether this new recommendation is more, less, or equally important where Huge Pages are implemented. More, less, or equally important in VM deployments? And, more, less, or equally important in ASM implementations?

Thanks much!
Steve