I had the FX 8150 on 4.4Ghz. Over that frequency, I couldn't gain any single frame. The architecture of the FX CPUs is designed in a way that ithey improve nothing over 4.4Ghz.
I am about to do the same on my Vega64, with the G12.
My personal recommendation about your topic: You don't have any reason to be concerned about the airflow with the configuration you propose. Anyway, the second configuration looks better. I would mount any of both.