I also have leg asymmetry. I use a shim, but that's not nearly enough. I use a saddle that's the exact shape and width of the bones of my pubic ramus, because that's what I perch on in my road position. My legs don't touch the saddle at all. Probably more help can be found by stretching, especially the hams. Look around for good cycling stretches or use these: IT Band pain (during ride)