Hi JohnnyB and welcome.
Well, I'm *coff* 46 (I think, at last check) and next week will be my 1 yr anniversary of having Cyberknife radio-surgery. My understanding that the standard "cut off" size for radio treatment of AN's is approx 3CM, so you are very fortunate that your's is very small and not in need of immediate medical intervention, where you can take your time and research, research, research. Mine was 1cm (10mm) at time of my treatment last year, so very safe at the size you note.
Hearing retention is usually in the 90's percentile with radiosurgery. Unless someone else here can provide specifics, since your AN is small, you should do well with hearing retention (I have retained 100% of mine for what it was at time of treatment). As we all know, all treatment options come with risks, so when talking to medical professionals re: your AN treatment options, please make sure you ask about hearing retention and the risks involved.
As others note here, no one can tell you which protocol is best for you. You are doing the right thing with the research you are doing. Inquiring to those of us that have endured treatments (all forms, micro-surgery and radio-surgery) is a smart move and why this forum board is here. That patient to patient connection will help you in learning more about how each of us are dealing with the our diagnosis, treatment options and outcomes. Our inboxes are open as well as many of us that are more than happy to speak on the telephone since sometimes, it's awkward to try to "write" what we are trying to say (trust me, I fail on that one all the time).
Question: Where are you located and as of now, have you researched any particular protocol so we can help narrow down answers and outcomes for you?
Hang in there and welcome. Glad you found us here.
Phyl