There are 4 pwn slots and I was thinking of installing identical fans for the rear to have even push and pull fan
Though I don't see an entry for 4 fans on cgminer status page
My psu is mounted externally so no issue with it.
There is no need to do that. stick with the fans that push fresh air in the unit.
This. Also one of the Avalon devs, I believe, noted that installing fans there would actually worsen the cooling due to how having fans on, both, the front and back would affect the airflow.
The best option, I believe, would be a more powerful fans in the front ... though those are already pretty powerful.
