HI LCT,
I do not profess to be a pro on CK but as to my research, I am more than happy to share what I do know.
All of the radio-treatments are viable treatments. I also checked Novalis at Brigham/Women's in Boston (where my neurosurgeon is based). GK locally was researched (at Tufts Medical) as well as Proton at Mass General Hospital. (I really am blessed that all of the options, as well as microsurgery are available here locally).
In speaking with the Novalis team at Brigham/Women's, the ultimate concern for me was the accuracy of the beam (my AN is still deep IAC with a hint peeking out to the CP angle region). In my case, accuracy was the utmost concern since it's still in the IAC and the dimensions of the growth. The Novalis website claims its accuracy to be between 2mm-4mm. The radio-oncologist at BW felt he could probably get within 1.5mm accuracy and recommended a 27 day course of treatment (for me and my living situation -- job, homelife, etc, to take 27 days off from work was not a good choice for me although I understand why he made the recommendation... he did note that he could bring it down to 5-days course of treatment knowing each dose would be far stronger).
In talking on the CK support forum, I remember one important thing. These dr's that volunteer their time to answer our questions are not paid to do so... nor are they apt to gain some of us as patients (due to our vast locations). I believe that they are willing to share their thoughts and opinions based on the patients they have treated. I have seen them note up front "based on my experience", so they don't claim to know it all. They have shared with me in my posts there their thoughts on meds, doses of treatments, etc. I don't take their word as G-d, but having done many CK procedures that they have, I listen to what they say and make my own judgement call. I have also spoken to many CK patients as well (some with historical data, some going through treatments now), which helped me with a patient's perspective as well. I tried to research CK from all angles to help me make a better informed decision.
In my research, I have heard that if micro-surgery has occured and regrowth has happened, the CK seems to be a viable radio-treatment for regrowth, based on accuracy. I am not aware of any of the other radio-treatments that can make the same accuracy claim as CK and maybe someone else here can elaborate on it.
I know CK is "newer" compared to many other radio-treatment options. True, there is not enough historical data to back up it's long term efficacy. But, for me.. and only me.... I have no issue trying this form of treatment, based on it's proven track record of accuracy based on the data avaiable today....
My understanding is that radiation is not "shaped" or "bends" but I think Mark or the dr's on the CK forum board can better answer that question. You are fortunate to live in an area (like myself) where there are many options. Surgeons are surgeons and they like to cut. Novalis is Novalis and Novalis practitioners like Novalis, etc etc etc.  Beth Israel has only had CK for 7 months, has done a few AN's (although they have done many brain tumors, including Meninginoma's). Do I wish they had more experience? Sure... you betcha. BUT, I asked where they were trained on CK, who did their training, how many brain tumors they have done, etc etc. For me and knowing Beth Israel's reputation, as well as the recommendation of other patients and dr's that are familiar with BI and their CK program, I feel, for me and my situation, I feel I made the right choice and look forward to getting this over.
LCT, I know for you and your situation... after your research, discussions, feedbacks, etc... you will make the right decision for you, regardless of which viable form of radio-treatment you choose.  Know that they are all viable... and in the case of post surgerical/regrowth, my thought would be to lean towards as best accuracy as you can get with minimal affect towards normal tissue structures.
I don't know if it helped, but glad to help if it does.
Phyllis
