I have only just started winding my own pickups, but I have done a little research on the issue. The number of windings are only one part of the whole. The shape, type and strength of the magnets, the gauge of the magnet wire, and even the pickup cover all influence the final product.
That said, many pickups will measure out to between 5k and 12k ohms per pickup, and 8500 - 9500 winds, depending on the wire gauge, will be up there in DC resistance. So for each half of a dual coil, you'd want to do fewer windings, at least according to my research. I've only done a single coil type, so I'm guessing with regard to the dual coil.