For winter riding in the wet Pacific NW, I made gators that consist of a stretchy wind barrier fabric and velcro closures that fit around my ankles under tights and over my boot or shoe tops. (I designed them for my cycling boots. They work sort-of with cycling shoes.)

The setup isn't waterproof but it does a very good job of guiding the water past my boot tops. Plus it is not a seal to the boot tops and I do not have to evacuate the house before I take them off.

And for the other approach: a lesson learned in 1977 when I rode my first "real" race, a 100 miler in pouring rain. Of course, non of us had waterproof anything. But the lesson? Those two or three holes in the soles forward of the ball of your foot? You want them! Drainage! The difference between wet feet and miserable feet in squishy socks. After the race, we heard the woes of all those riding shoes without drainage. Those of us with felt pretty smug. If your shoes do not have those holes and a rainy race is coming up, pull out the drill. (Three 1/4" holes in a triangle of 1" sides where the ball of your foot meets the base of your toes will do nicely. Any shoe that is compromised by such holes is not a very well designed pair of shoes if they were intended to be raced.)

Ben