I would say go for the resale and use the 7 month window to book at BCV. Over time, you are going to want to stay at many of the
DVC resorts and paying a premium to have BCV as your home resort doesn't sway me.
If you are set on buying and know you're going to do it, I would do a little extra legwork over the next week or two, and try to make your purchase immediately - cancel whatever cash arrangements you've made for your Sept. trip, and stay on DVC points. Another alternative, if you are set on buying and decide you will be buying at BCV or other resort from DVC, call and speak with a guide now - tell them you are coming down in Sept. to buy, and see if they can arrange discounted pricing for you to stay at BCV or another DVC property - again, I would think you would be able to do your Sept trip for very low cost.
Though it makes sense to buy contracts in smaller amounts (as many folks here say), if you are buying the resale, you will pay closing costs once for each contract. I forget how much the fees come to with DVC (or if they're included), but with a resale, guaranteed you're going to be paying a couple hundred dollars on each one - so, you will need to look at the tradeoffs of a large contract vs. smaller contracts and more closing costs.
I've learned that the best benefits come from DVC if you are flexible. At times, you might not be able to book at BCV with the 7 month window, but, right now, there is no problem. Whenever DVC opens a new resort, people get fanatical about that property and owning there. Overall, I think it's a moot point. Your DVC membership allows you to stay at any of the DVC resorts. We bought at OKW, sight unseen. Turns out we love OKW, but also enjoy VWL. We adore the times we've stayed at the Beach Club for cash in the past, and will no doubt enjoy our stays there in the future on DVC points. We're flexible, we've always gotten to stay where we want, and we're not overpaying for our DVC membership.
Lastly, just keep in mind, that long term, your DVC membership will be worth absolutely nothing. DVC gets it back, and you get nothing (unless you sell before that happens). So, consider the amount of money it will cost to purchase, the annual dues, and that at the end of it all, you will not have anything left. My personal advice to DVC purchasers - don't finance. It makes little sense to finance a depreciating asset - especially when you're not getting rock-bottom pricing.
Good luck however you decide. We'll look forward to giving you a round of "Welcome Homes" in the near future.