Here is my experience: I have just completed successfully walking a reservation at 7 months at the VGC this morning. As it turns out, had I not walked it, even at 7 months, I would not have been able to book my reservation and would have needed a prayer for a waitlist.
When I started this I noted two very specific things:
1. I would aim for my preferred dates, but would arrange my vacation around what I was able to secure. So if holes appeared or an 11-monther swooped in, I was prepared to use whatever dates I could.
2. I was only technically "blocking" 7 monthers at this point. This actually didn't even apply as almost immediately days become unavailable in the middle of the reservation.
It seemed like for most of these days, there were only ever 1 or 2 studios in play which made it stressful and always being at the ready at 8:00 AM. In the end, I got my preferred dates and I feel the extra work was worth it.
This is not like DisneyWorld where sometimes you need to "settle" for OKW or SSR. Its pretty much one and done so the extra work was well worth it here IMHO.