I think this is a pretty complicated question. I don't think it's essential that you have perfect symmetry between the two sides. Most people are not perfectly symmetric. For example, I use a spacer under one of my cleats because one leg is longer than the other. I think what is important is that you don't make any asymmetry in the system worse when combined with the asymmetry in your body. If you worsen this asymmetry, you may get discomfort or an injury. The only way you would know is to have a good, experienced fitter check you. Or, you can just try it and see if you develop discomfort and stop and change back if you do.