IMO, if you really want to stay at BLT, then I would buy there. While I do think that getting LV rooms at 7 months has been pretty consistent, there are going to be times that you might have difficulty.
How frustrating is it going to be for you to find out you can't get in there and wait list and then that doesn't come through? Fo us, we bought BLT to stay at BLT because I decided spending a few thousand dollars more--we bought in 2009 when it first went on sale--was worth not having to worry about getting the rooms we wanted. Plus, owning there allows us to book SV rooms which stretches the points and puts them in line with the other resorts we enjoy--BWV, BCV, and VWL---for the times we travel.
As mentioned, I would really look into resale and possibly just buy the points you need for staying at WDW and maybe looking into another timeshare to take care of your other needs. But, as mentioned, currently, both resale and direct can trade through RCI.
Of course, when you buy DVC, you really are buying the right to stay at your home resort, and while I think highly unlikely, they could remove a resort from the "club" and then you would be limited to your home resort only--direct or not.
So, if you are comfortable staying at SSR if BLT isn't available, go with that--but, if disappointment or frustration will set in if you are there, then go with what you love.
Good luck!