Debbie, I would get several opinions from AN specialists before making your decision. Dr. Steven Chang (from Stanford University Medical Center) is arguably the most experienced CK specialist in the U.S. and perhaps the world. He will review your MRIs and medical history and give you his recommendation for free. His email address is sdchang@standford.edu.
If it were me, I would choose the least invasive procedure possible, seeing as you already have a traumatized facial nerve. CK and GK are roughly the same as far as accuracy goes and -- as far as the facial nerve goes -- are both non-invasive. (GK does require screwing a crown superficially into the skull, whereas CK does not, but this has no effect on the facial nerve.) The fractionation (splitting up into several doses applied on different dates) that CK employs does give it a slightly better chance of preserving the function of the hearing nerve. I would ask Dr. Chang if the same holds true for a facial nerve that has already been degraded. Normally, the preservation of facial nerve function is not differentiated with CK and GK (as it is with the hearing nerve) because the facial nerve is considered to robustly withstand either type of radiation treatment. But for an already-damaged facial nerve, I suspect that fractionated radiation treatments (CK) could possibly be gentler on your weakened facial nerve. The usual caveats apply: I am not a doctor and this is a personal choice only you can and should make. But I highly recommend you ask Dr. Chang whether he thinks a fractionated approach (CK) would likely better preserve your remaining facial-nerve function vis-a-vis the single-dose (GK) approach.
Dr. Chang also does microsurgery on ANs, so you are likely to get an unbiased opinion as to whether radiation or surgery is your best option.
Best wishes,
TW