For the feet I use this one. It’s working well. feet Amazon
The cooler you are using is great.
Do you have exhaust fans (you should at least have a slim one under the PSU). If you have a top hat you can have 2 more.
I recently got these for my Ghost S1: https://www.amazon.de/-/en/Oehlbach-Effective-Resonance-Dampener-Absorber-black/dp/B0047T6WXY/
They have a larger diameter and are roughly double the height of the stock but don’t give it a floaty look in my opinion and still improve airflow. Plus they basically look stock :D.
I went for the same solution for my front speakers with these.