The immaculate documentation presented in CofC was one of the first things I noticed the first time I read the book. It spoke to me of someone who was prepared for an exposé. Which would add credibility to your way of thinking.
I was an elder during that time and had a fleshly brother at Bethel. I remember hearing of Spanish Brothers imploring ALL present at the Memorial to partake as they were all Anointed. This leads me to believe there was a coup type mentality of some. It certainly would not have gone unnoticed by Ray. Remember, Ray was one of the principle ones to advocate for less power of the WTBTS presidency. Of course, no one can read Ray's motive. A friend who had a very responsible position at Bethel at that time and knew Knorr well, has told me that Knorr felt that Ray had designs on the presidency. Of course, that is just his opinion, but knowing him and his demeanor, I believe it to be true.
When I resigned as an elder I had a number of letters that had been written regarding elder matters on my computer and I had made copies of some policy letters from the Society that I would refer to, but nothing like the documentation Ray presented in his book. AND it is this documentation that, perhaps more than anything else, convinced me that Ray's claims were true and verifiable. It shouts to me that he had an agenda when he left Bethel. Doesn't bother me except that it suggests "he was gathering evidence while on the inside" as you mention in your post.
Ray's books had a tremendous effect on my thinking, and his way of writing, without the flaming apostate attitude I was led to believe I would find by WTBTS, impressed me greatly. However, I believe he knew what he was eventually going to do when he left if he could not make reforms from the inside.