I hope I do not throw your decision up in the tizzy but when I read your post I felt I had to respond to let you know what my experience has been. And I think you'll see how varied outcomes can be.
Had total hearing loss when my 2.5 x 2.3 x 2.5 cm AN was diagnosed. Total hearing loss was sudden. Had started noticing a slight hearing loss a few years prior to diagnosis. Neuro-surgeon recommended GK. With GK had minor improvements in balance, facial movement and taste. No change in hearing but developed double vision. Two months after GK started having seizures, tumor had swelled to about 3.0 x 2.7 cm. Lost consciousness a number of times, got placed on anti-seizure medication. Neuro-opthamologist said high pressure causing optical nerve to swell thus double vision. Neuro-surgeon recommended tumor removal as it was compressing brainstem even though tumor showed necrosis. Checked into hospital that day, retrosigmoid surgery the next day, no time to research. Tumor was debulked, it was sticking to the nerve and brainstem so it could not be completely removed. Surgeon said the tumor center was liquid and outside was like orange rind so I think the GK was doing what it was supposed to do but maybe too good and swelling became a problem.
Day after surgery noticed taste was quite improved and I told my husband "I don't know why I think this but I think I'm finally going to get better." (After GK recovery was kind of up and down even though overall I thought I was getting better.) Went home 3 days after retro surgery and was on the road to recovery. Two and a half months later returned to work part-time and a couple weeks after that full time.
Two months after surgery started hearing very high pitched sounds -- birds chirping while I went for walks to gain strength and work on balance. Five months later could hear a broader range. Nine months later hearing was tested and was at 75%, considered mild-moderate hearing loss. Now, at two years, hearing loss is still in the mild-moderate range but have tinnitus which has gotten "louder" in the last couple of months but is bearable. I cannot complain as hearing was the one thing that all the doctors said would not recover.
At 16 months, tumor was down to 1.0 x 1.7 x 1.8 cm...may not seem like much but it looks shriveled in the MRIs. Two years later, am doing very well, no double vision, balance is good, taste (and weight) and facial movement are back. Will be scheduling my two-year checkups soon.
Best of wishes to you on your decision.