I don't own at VGC, but I have stayed there, and I have tried many other times to reserve. I have even been PARTLY successful a few times, but never for anything near as long as the length of reservation you want. In my experience, studios are almost impossible to get at 7 months.
I once said that Bigfoot is more likely to walk through the lobby of the Grand Californian than for Non VGC owners to be able to stay at Grand Californian by exchanging in with their
DVC points.
That is a bit of an exaggeration, but not much. The trouble is, not only are there only about 50 units (75 if you count the Lock offs as two units) but it is such an incredibly desirable place, quite likely the single most desirable DVC Resort anywhere. Grand Californian is an amazing resort with some advantages (access directly into Downtown Disney and into California Adventure) that no other Disney resort has EVER had. And, it is the only DVC property in
Disneyland. Add to that the fact that Disney has sold an awful lot of their Aulani points to people in California, by 'suggesting' to the Aulani purchasers that 'they could always use their points to stay at Grand Californian, at 7 months,
if there is availability.' So there is demand on top of demand on top of demand. It is a perfect storm of incredible desirability, and almost no availability under the best of circumstances.
So, I don't want to be a Dickie Downer, but I think there is almost as much chance of it snowing at Disneyland, as you getting 5 nights in a studio at the 7 month window.
That being said, most of the units DO have some availability right up to the cusp of the 7 month window. This often includes Studios, 1 Bedrooms and 2 bedrooms. But, to have any chance at all, you will need to be online, ready to go, right at the tick of the clock at 8 AM Eastern Time (5 AM California Time) at the opening of the 7 month window on the appropriate day. If you are GOOD at doing it, AND lucky, you might be successful. You can greatly increase your chances by starting as early as you are willing to, considering the extra work, and try every morning to get it until you are successful, and then walk it all the way into place. It is true that the VGC owners can still jump past you, and block your 'walk,' but there is also a decent chance they won't, so you should probably try that.