The only reason I don’t offer comment on the space inside the cup is that most times, thanks to the angled nature of that area, it’s an awkward and complex 3D shape that’s not easily measured. Often, manufacturers will also tell you how big their pads are either on their web site or if you ask them nicely.
If you’re having trouble finding a good fit, I’d recommend focusing more on pad size than driver size. The driver is the speaker that vibrates to make audio, and two headphones with the same driver size can have wildly different cup/pad sizes. The driver size doesn’t necessarily tell you anything about the fit of the pads.
For instance, the M50X uses a 45mm driver, but it’s inside a much smaller cup with a smaller pad than the DT770’s 40mm driver.
Most consumer dynamic headphones use 40–50mm drivers. Some of the models mentioned in that thread you linked are planar magnetic…and those are much more spendy.
Further complicating things is the subjective nature of headphone comfort.
Some folks loathe having things touch their ears…it sounds like you’re in that camp. I usually am too, although there are exceptions. The Plantronics RIG 400, a smaller gaming headset, makes contact with my ears but the foam is nice enough that I don’t mind it.
All I can do is offer up some suggestions of headphones that have bigger cup/pad openings than the Cloud X, based on my experience.
If you want to stay with HyperX, their Revolver headsets have absolutely massive pads and openings. They seem designed specifically for folks that are sensitive to ear touching.
Beyerdynamic’s DT 770/880/990 series is great, even though they have round ear pads. They’re taller and wider than the HyperX Cloud X pads, and deeper too. And the foam inside the cups is super soft.
Do you have any Bose kiosks in your area? If so, try on a pair of their QC35’s. If those don’t fit you comfortably, then I’m sorry to say that most headphones, even those often ranked as “comfy” will probably be on the small side for you. The QC35 has one of the more spacious ear areas of any consumer headphone.
Other good big choices: SHP9500, Audio Technica AD700X, Sennheiser HD500/600/700/800. The 598Cs is good if you want to stick with a closed-back and don’t want to break the bank.
Thanks for your comments and feedback! I’ll try and do a better job of talking about comfort of the ear cups in the future…but I’m also more focused on relating my personal experiences than being an objective measurement site. There’s already several of those, and they get a lot more…opinionated commenters than I do, haha.