So I thought long and hard about using these back-to-back clips for a 4-channel setup using the stereo bars. My conclusion is that it is not a good solution if you need to use windscreens. It might work if you're running delrin bars of differing lengths, but not at all if you're running 2 x 17cm bars and poorly if you're running 1 x 17cm and 1x 20cm.
Ultimately, I went with a K&M stereo bar oriented vertically with two Shure A51M's (or you could use A 20's). It works extremely well and allows as much vertical spacing as needed for windscreens.