Hi Martha,
It looks like you are the classic example that the size of the AN is not as important as the symptoms it produces, severe vertigo and tinnitus in your case.
I have a 9mm AN in my left ear (diagnosed in 2013) and have mild tinnitus and imbalance issues, but no vertigo unless I do something stupid like look up and try to turn around while doing so. Walking in the dark is also very difficult as my brain has been using my vision to make up for my balance nerve loss.
I do have a lot of problems walking on uneven surfaces. I love to fly fish and two years ago was wading on a river with an uneven bottom and fairly slow currents. In the good old days, this would have posed no problems at all. But on that day, I fell into the water twice and had numerous other near misses and knew my wading days were over, but I was not sure why I had lost my balance so badly. Shortly thereafter I had the MRI and discovered that I had an AN, which I knew nothing about.
Like you, I chose to W and W, and have been very active square dancing, typically three to four times per week during the fall, winter and spring, which I think is great therapy and much more enjoyable than PT.
It sounds like you are mainly considering surgery. Have you given much thought to Radiotherapy? Either Gamma Knife or Cyber Knife? Do you have a ANA support group in your area that you can reach out to and meet with? There are also lists of ANA members who are willing to talk with you on the phone to discuss your feelings, issues and concerns.
If you do consider surgery, all the literature I have read says to go to a doctor or group that does lots of these operations on a yearly basis.
In any event, good luck to you and keep us posted. We are all in the same AN boat!
Rod