As long as the side toward the beer is lower, this means CO2 pressure is pushing down on the water. This indicates that you have at least some degree of seal on your lid and don't have to worry about things getting in.
I use the S-type with water/shine and never had an issue with evaporation. I've actually got a forgotten experiment from a friend that's been sitting in my laundry room for over a year and the airlock is still full enough (not what it used to be, but hasn't evaporated dry yet). I need to get rid of it, I'm sure the bucket is now tainted beyond use, but as long as the airlock is preventing it from stinking I'll let it sit there harmlessly instead of finding out what the inside looks/smells like :cross: