Studios typically save the most w/ renting from a
DVC owner. The 1 br.s take a lot of points & if Disney is heavily discounting their cash rooms a
DVC rental for a 1 br. may cost about the same as a cash rental through Disney. But Disney usually only releases discounts a few months ahead of when they’ll apply & by that time popular DVC villas are already booked.
OP, owners can book their home resort (where their points are) from 11-7 months. Those who own at more popular resorts tend to book them during this home resort priority booking. At 7 months owners can book anywhere (except Riviera for some resale owners) & many owners switch from the larger/less in demand resort they own at 7 months to book a smaller/more popular resort further reducing available villas at popular/smaller resorts.
Another factor is view categories, typically views that require more points such as BWV preferred view, AKV Kidani savanna view, Poly water view, (& I assume VGF resort studio water view,) etc., will be available longer than views that take fewer points. There’s also seasonality to demand, some times of year are especially tough & some times of year & holidays cost more points than others.