Need more volume with my aviation headset (David Clark OneX). I wear hearing aids
This is a decent article to take a look at but you may want to consider the clarity aloft headsets which use hearing aid speakers and seem to be able to serve as a nice drop in replacement.


  I have a hearing loss. Can I use this headset with my hearing aid?
  
  Because our headset uses high quality hearing aid speakers, the pilots
  who have hearing impairment just remove their existing hearing aids
  before putting on our headset. A balance control can be adjusted to
  favor one ear with louder sound. We have many pilots who have a range
  of hearing problems from mild to moderate.