As the others said, you'll want to get your request in ASAP if you're only a few months out from your vacation, and be as flexible as possible (with second, third, and fourth choices queued up). The biggest downsides to DVC rental are: (1) the requirement of immediate payment in full once the reservation is secured, and its non-refundability, which my family has typically accounted for by purchasing vacation insurance; and (2) you won't be eligible for any Disney special offers (e.g., room discounts, "free" dining offers) that come out for your dates.
We've rented from David's for 3 stays: one at Wilderness Lodge in a 2-bedroom DVC villa (saved ~40% off of rack rate); one at Beach Club in a studio villa (saved ~50% off of rack rate); and one at the Polynesian in a studio villa (saved ~33% off of rack rate). Each time, I made the request at 11 months out. In each case, David's didn't instantly have a member with the points needed for our request (and with the right "home resort"), but each time, I asked that they hold onto our reservation request in case somebody listed the points we needed.
For those three resorts, within a few days (and in the case of the VWL request, a couple of weeks) David's got a member with the right resort/points, and secured our reservation. After that, all arrangements went flawlessly. We linked the reservation numbers to MDE and proceeded as normal. (If you want the DDP, you will have to arrange for the member from whom you're renting to set that up for you.) When I had questions, I called David's and could immediately connect to a representative who was friendly, knowledgeable, and on-site (not somebody in a call center in Bombay).
The only time David's wasn't able to satisfy a request, we had wanted to stay at Animal Kingdom Lodge in a very limited room category. David's couldn't satisfy it immediately, and the category was fully booked within a few days. (One important thing to understand about DVC rentals is the difference between your desired room being unavailable -- that is, fully booked so nobody can reserve there -- and your desired room being available, but the DVC agent simply hasn't had a member list points that are appropriate to your resort/dates/request size yet.) David's let us know the room category was unavailable, and offered some alternatives. When we declined those, our deposit was immediately and cheerfully refunded.
...another consideration for you OP, given the timing of your trip. You'll be traveling during Epcot's Food & Wine Festival and the Epcot-area resorts are often packed during that time, which means if you're hoping for an Epcot-area resort (Boardwalk or Beach Club), there's likely to be almost nothing available at those particular resorts by this point.