1) Make sure that you remove that knock sensor. It's at the low point in the cooling system. When you do, use an awl or something and make sure that there isn't any scale or other debris blocking the hole.
2) You asked me about the method that I use. No anti-freeze at all, just very careful about draining. never a problem in 9 years of cold Canadian winters.
Finally, I remove the pitot tubes at the bottom of the little brass ballast tubes located in the space behind the back seat on either side. Then I blow the water out with my mouth...if you cant do this the pick-up is clogged, and you should clear it with a large safety pin.