The EX1000 would top the scale for me. Even at low volumes it was fatiguing and painful. I'd have to listen at baby volumes and at that point the IEM would have no dynamics (the EX1000 need juice to open up). The MDR-7550s are not an issue for me though and is the saving grace to the EX line IMO. Although I can't listen to them at very high volumes as I'll get fatigued. But that's not due to the treble spikes causing me pain. Just not listening at safe volume levels. I can't say the 334s would be on the bottom because I picked up treble spikes even on that which would get a bit fatiguing for me at higher volumes. Then again its bloated bass (slow bass decay) was rather annoying and would keep me from raising it too high anyways.
The difference between the EX1000 and MDR-7550 is actually only a few dBs, with both Sonys being more spiky than the TOGO 334.
Don't get me wrong, I don't doubt your treble sensitivity, but it seems odd that you picked up spikes on the EX1000 and TOGO 334, but not on the MDR-7550.