Just to confirm I have made an account. I have successfully mounted an 140MM EKWB CE in the back, 360MM EKWB PE in the TOP, and an 280MM EKWB CE in the front.
Everything just fits, the screws of the 360MM are almost touching the 280MM rad because EKWB uses ball shaped screw heads.
But it does work, and it works great!
From what I can tell you can even fit another 120MM PE in the bottom, but I didnt do this, so try at your own risk. Looks like plenty of space though.
As a PSU I am using a Corsair RM750x, so that PSU and a 120MM would work!