But then Factor in the MM and its 6/8192 chance of a shiny... i need it to be both that and DW.
*Sigh* Im going to kill my friend... i know in my group of friends im called "the breeder" but this seems hard even for me.
I'm assuming you want a Timid Vulpix (as that's the most common nature that Ninetales runs on a Sun team), so I'd make sure either the DWF you have or the male is Timid, holding an Everstone. In B/W, the chances of an Everstone passing on the nature are 50%.
So to get a shiny, Drought, Timid Vulpix, the chances are (1/1365)(.4)(.5), or .015%, in Pokemon Black/White. However, if you were to do this in B2W2, you would double your chances of getting the combination you want, because in B2W2, the chances of the parent holding an Everstone passing down its nature was changed to 100%.
So you'd have (1/1365)(.4)(1), or ~ .03% chance of getting a shiny Drought Timid Vulpix.
If you don't care about the nature, then you have a .03% chance of getting a shiny Drought Vulpix with any nature on either game.