I have used these for several years…medium in left ear, large in right ear…no feedback. They are very comfortable.
I have to say that my experiences are similar. On the advice of an audi at Costco I had ear molds made, hoping to filter out extraneous noises. That also involved readjusting the hearing aids so that the microphones would work with the ear molds. That worked fine for a while, but I found myself really having a hard time with TV and conversations. These were exactly the same situations that the moles were supposed to help. I want to see another audi to have my settings adjusted, and he asked why do you have molds? I told him because they were suggested. I ended up taking off the molds and reinstalled open-fit domes and feel I can now hear TV and conversation better, but do get whistling because the programming was meant for molds and not domes, if that makes sense. I’ve not bothered to go back for correction because I’m about to pull the trigger on KS9’s. My current KS5’s are now over 5 years old.