607 definitely was the kickstarter, it opened my mind up to the fact that the organization will willingly hold to false information because of held doctrine. This shook me to my core because before I found this out, I had believed that 607/1914 was our most firmly researched and valid beliefs.
If they lost 1914/1919 then the GB wouldn't hold their claim atop Mount of All Lies, so of course they won't admit to being wrong, they have EVERYTHING to lose over it.
Finding this out removed my previously held notion that I shouldn't question the GB, and replaced it with, I should question EVERYTHING!
It only took me about 6 months or less to drop my belief in JW doctrine, it would take me another year to drop my faith in the Bible. I think I knew the Bible was wrong early on, but I wanted it to be right, so the internal struggle of wanting it to be true vs. my critical thinking raged on for about a year before I finally obliterated my faith completely.