PVB has a total of 360 studios and there are only two studios at PVB that do not connect. The two non connecting studios are on the first floor of the Tokelau Longhouse and are considered Standard View studios.
Like others who have posted, I have yet to hear of anyone who has not gotten their request for connecting studios. If I recall correctly, even before
DVC came to the Poly the resort was very good at granting guests' requests for connecting studios.
If having connecting studios was important to me, there would be a few things I would do that might improve my chances:
First, I would not make any room requests other than "connecting studios." I wouldn't want the room assigner to think my desire for a specific location (such as high floor or near elevator) is more important than connecting rooms.
Second, (since each room is a separate reservation) I would let Member Services know that I am "Traveling With" the other reservation. DVC is pretty good at trying to keep all "Traveling With" reservations together, or at least close by. By putting the "Traveling With" designation on the two reservations, it might increase the odds that I will actually get connecting rooms.
And third, I would book Standard View studios rather than Lake View studios. There are a lot more Standard View studios (288 studios) than there are Lake View studios (72 studios). That means there are 143 possible pairs of connecting Standard View studios compared to only 36 pairs of connecting Lake View studios. Just by the sheer numbers, the odds of getting connecting Standard View studios should be better than trying to get connecting Lake View studios.
Good luck!