Tintax

The Duke is a great cooler and you don't need an aftermarket gpu cooler to oc. 
The front supports either 120mm or 140mm's depending on what you want to use. Which is better depends on the specific fans being compared.
Front intake and rear exhaust is great. Top exhaust can also be helpful but might be overkill. The stock case fans should be fine for most systems. What are your specs?

https://www.gamersnexus.net/hwreviews/2301-most-comprehensive-corsair-400c-benchmark-review-specs
 
This review is very comprehensive test on Carbide 400C fan configurations.
Just read all, and follow it..

Tintax can’t help you at this moment but I purchased that same case and it will be delivered Tuesday this week. I’ll let you know what’s in it when it arrives.