I do not subscribe to the philosophy of turning over the engine (whether it's 20 blades with the mixture out or by hand). Doing so will not distribute oil evenly (remember, much of the lubrication depends on oil splashing, and the oil needs to be hot and less viscous to splash effectively [turning the engine over 20 blades definitely will not produce hot oil]). Furthermore, turning the engine over WILL scrape the oil off the cylinder walls, making them more prone to corrosion, and it WILL draw that moisture-laden air into the cylinders.
If you preheat the engine in the winter be certain not to leave the heat on for prolonged periods (I.e., for days at a time). Doing so has been shown to increase the amount of condensate forming inside the engine, hastening the formation of corrosion.
You can try blowing dry air into the crankcase through the crankcase ventilation tube. Devices for doing this are advertised in Trade A Plane and the EAA Sport Pilot magazine. These devices draw air through a desiccant, then blow the dry air into the crankcase.