Oh wait, I just did a batch of Sweet William and it sprouted in two days, but that isn't winter sowing now is it? I also just sowed three varieties of the Arizona series of Gaillardia's and lots have already sprouted. The only WS Gaillardia I did was Tojaker. I got three sprouts out of about 15.
I had good luck WSing Penstemon Electric Blue, ZERO luck with Penstemon Iron Maiden. I just resowed Iron Maiden and stuck it in the frigde. I will pull it out around Memorial Day and put it out and see if I have any success.