I would ask what kind of closed domes you have tried. Different ones allow differing amounts of air in and out. I personally prefer Phonak closed domes. They have two large holes punched in them that usually allow plenty of ear in and out, but still do a better job of feedback control than Oticon open domes. I would suggest give them a try. And as others said, keep your ears cleaned and moisturized.
Phonak/Unitron Closed - Large ( OP601369) which she modified by cutting holes in the domes with small diagonal cutters. Three holes in one and four in the other. My Oticon domes that do not give me the ear infection problem (but that do allow whistle/feedback) have 6 holes in each one. So they “ventilate” at 2x to 3x as much as the modified closed domes.
Something in between those two levels of “ventilation” might work.
I will see if she has Phonak closed w/ 2 holes.
With your loss, there shouldn’t be that much feedback. Phonak has “closed” domes which have the two holes punched, and they have “power” domes that have two layers and no holes. For your loss, the “closed” domes with two holes should be more than adequate to control feedback. If you feel a bit plugged at first, I would not be totally surprised, but that feeling should go away on its own as your ears become accustomed to the change in air pressure. Its just a matter of putting up with the change for a few weeks.
Hi Justin,
Thanks for keeping up on my thread. Saw my audi today. She is so nice & a beauty to boot. Any way on the “essential oils” she said that they did not really address my issue, which is MOISTURE causing SWIMMERS EAR type problem & she & I both agreed plain old alcohol is probably the best way to control that.
As for the domes, without a part number, she pulled what she thought you were talking about & the openings were like small slits, smaller than the ones she custom cut for me previously. So they would not allow “air drying” to happen, unless you were referring to some different Phonak domes?
So, she gave me a few 100% Phonak closed comes so that I could experiment with putting some openings in them & trying them & see if it helps with feedback/whistle.
I will do some modifications & post back some results.
Thanks again. Appreciate your thoughtful input.
This is a Closed dome. You will notice it has what looks like a tiny hole or pimple. 
This second picture is a Power dome. It looks like it has two layers, but no holes or slits or anything.