Generally what I do is just decrease watering in the winter. I never give them a true dry period because half my collection never goes dormant. As soon as it starts warming up, I start watering more regardless if the Pings are dormant or not. I use the tray system as well. I think the trick is to not allow the Pings to be wet all the time. I always let mine dry out quite a bit between waterings. I wait until the media is almost dry to the touch. Then I refill my tray and wait about a week or so (or until the media is almost dry again). Of course this is what works for me in my conditions. The same may not be true for you.
I moved a little over two years ago. Before moving my Titans never went dormant. Now they have decided to stay dormant about 75% of the time. The other 25% they actually grow and produce carnivorous leaves. Even with it being almost 80F under the lights in the summer time, they still remain dormant. I don't get them. I have a friend that I sent some Titan plantlets to that grows in a greenhouse. He experiences the very same thing. His Titans only grown when they please and it's for a very short time.
I had a p. titan and it did this too. I grew sick of the plant.