I was just going off what james444 told me via PM:
"Hi there, yes fit may be a concern in your case, since their housings are pretty large. Particularly if you like to wear them downwards. A friend of mine with smaller ears tried my FX850/750 and he had less issues with them over-ear. The nozzle is angled in a way that places the earpieces almost parallel to your ear in that case, and you don't have to fit the whole diameter of the housing. For some reason he even preferred the 850 over 750 for comfort.
But downwards and small ears is potentially problematic, sorry to say."
Out of all the IEMs I've used, the XBA-H1 was the only one that the housing size caused a problem. It hasn't been a problem with the SoundMAGIC E10, JVC HA-FX101, Xiaomi Piston or the Zero Audio Carbo Basso.