So I can't really claim to be an expert but in my long hours of research I have an opinion that adding any more rad area, however slim, is superior to thickening up an existing radiator. Generally thicker radiators need to have faster fans to keep up with more radiator space. Faster fans = loud, which I cannot abide. If noise isn't a concern, thick radiator + fast fans is certainly very performant.
With an mATX board in Cerb-X you'll have ~100mm between the bottom of the case and the edge of the motherboard. With 32mm dedicated to fans, you've still got a massive 68mm of potential rad thickness. If you're only using the first (top) PCI slot for your GPU, that's another 50mm or so of space (overlapping with motherboard) for a potential horizontal res/pump.
Hard drive will be... tricky. Power cables don't bend sharply... you could consider getting an SFX psu over an SFX-L, which would save you 30mm of space (a TON) for cable routing!
Mocked it up for you (note that I'm too lazy to model screw holes in these tinkercads so fine placement could be off - but hopefully not to a disastrous level. 32mm fan height, 60mm rad thickness. Also note that the PCI slots on the case are going to be fucky because I just stretched the cerberus model taller to make it a cerb-x. You can totally flip around the bottom radiator, too, so the ports would be towards the rear.