Try angling them a little bit and see how you like the sound. As with everything on your kit, the trick is to adjust away and play around with it till you find how you like it.
Personally I don't use the tilt screw because I use 15" has and don't find air lock a problem. YMMV so adjust till you're happy.
I have never experienced the "air lock" either. I always keep the two cymbals parallel. I've always thought of it as a sound preference thing. I prefer to control the sizzle with a ratio of how hard I hit it, and how much I open it.