Interesting, thanks!Hoping to get the time soon to put it together!!
This was interesting experiment on the topic:
Something else to take into consideration is each fan setup (ie fan on front, on back and on both) is not just changing airflow thru cooler but airflow thru case. This is adding variables video not being taken into account by video author. These other variables may be small, but with only 2.2 difference it could be result of changes in case airflow and/or combination of both case and cooler.