With a cookie bite type of loss like this, I would recommend your focus in doing research on this forum be a couple of things → 1. Find members on this forum who have a similar type of cookie bite loss like yours and try to get them to share their experience with you. 2. Try to do some research and see if any particular HA mfg(s) may have their proprietary fitting rationale designed to address the need of cookie bite patients.
For item 1, the first person that came to my mind is Tony (@Abarsanti). Since I tag him here, maybe he’ll pop up and chime in to help you out. If I remember correctly, he used to wear the Oticon OPN 1, then he switched to the Costco Philips HearLink 9030 for a short stint before he settled with the Oticon More 1 now.
For item 2, I don’t know much about HA mfgs other than Oticon because my current pair of HAs is the Oticon OPN 1. Thus I’ve done research on Oticon technologies a lot, and I remember coming across an Audiology Online presentation by Donald Schum (who used to be VP at Oticon but is now with Whisper), and in this article, he addressed the issue of the cookie bite type of loss and how Oticon researched and came up with and incorporated into their VAC+ fitting rationale measures to support cookie bite loss patients better. I don’t know if the Philips HearLink 9030 sold at Costco has a fitting rationale similar to the VAC+ or not, but it’s likely that they do because they license HA technologies from William Demant who is the parent company of Oticon, Sonic and Bernafon.
That is not to say that other HA mfgs don’t address and support the cookie bite type loss patients. I just don’t know enough about non-Oticon fitting rationales to be able to say anything helpful about them.