I'm actually only using one fan per cooler. The other cooler is just being used as a backplate and passive cooling. Overall the Antec coolers were a quick install and work well. As a side note I'm getting better temp control with the supplied grease vs. Fuji Poly thermal mats I bought.
Grease only chip side. Having two Antecs back to back allows me to screw them together tightly without board flex. On the back I am using some Kapton tape as a insulator (thanks Mr. Teal for all the suggestions).
I will turn on the backside fans later in the week when I get some 4pin to 3 pin adapters. I couldn't fit two 4 pin fans on the Chili (only has two 3 pin plugs really close together)