Hi, Paul - and welcome.
I'm never happy to learn of someone else being diagnosed with an acoustic neuroma but since you have, I'm glad you found the ANA website/forums.
You outlined your situation quite succinctly and we can all empathize with your angst as you face making a treatment decision. I certainly wouldn't presume to offer any specific advice because (a) I'm not a doctor and, (b) you seem to be on track - with plenty of information about each option (surgery/radiation) and you are aware that both carry inherent risks.
One issue you raised that I'll comment on is that you assume that no matter what treatment option you chose, you'll have regrets, later. That is not necessarily so. Not every AN patient - surgery or radiation - encounters difficulties. Some that do find any complications are temporary and some, like me (I had both surgery and radiation) have virtually no complications. That could well be your experience but, as you well know, treatment outcomes can never be guaranteed. I had no choice but (debulking) surgery (4.5 cm ) and it worked out fine. I hope your treatment -surgery or radiation - will too. We're empathetic and offer our encouragement, experience and support, no matter what option you ultimately chose.