Sometimes, very difficult and other times, not so much. For example, October during Food and Wine is very tough.
But the question is how happy are you going to be if you can't get what you want at BWV for the entire vacation?
If you will be disappointed not staying at BWV, then I would suggest buying there and not at BLT.
We bought BLT because we didn't want to hope that we would be able to get the room we wanted at 7 months. We love being able know that we are we love. We considered SSR, as it would have saved us $5000, but in the end, not worth the risk.
Now, we did trade out at 7 months this summer to a BCV studio for 3 nights without a problem but had that not been possible, we would have been fine with BLT as it is our favorite resort (we are doing that last 3 nights of our vacation there in a 1 bedroom).
IMO,
DVC is expensive and a lot of money to buy someplace you really don't want to be and there is no guarantee that it you will get what you want.
Of course, if you don't book until the 7 month mark anyway, then it doesn't really matter.
Good luck!