Welcome Daydreamer -
as others have said, 1.5 is considered the higher end of small and the lower end of medium. At this point, both radiation and surgery are usually possible treatment options.
The key to choosing a doctor and a treatment is doing your research and then deciding who and what is right for you; make sure you find someone who has a lot of experience with ANs. If you feel you need more than one opinion, go with your feeling. If you find a doctor that you are comfortable with and feel confident about, you may decide to stop there. There is no wrong or right answer.
I chose surgery with the first and only doctor (neurotologist) I consulted with. I talked to him both in person and on the phone several times prior to my surgery, but I didn't consult with anyone else (except for the neurosurgeon, once I scheduled my surgery). I was, and still am, very comfortable with that. That was my choice, but it may not be yours. Others have consulted with lots of doctors. Do what feels best to you.
Good luck, and remember we're all here if you need us,
Jan