Something that I would never do to my clients is to affect their natural beauty.
I came across case studies in seminars where eyebrows asymmetries was dealt by trainers by shaving off half of the model's eyebrow and replaced with a tattoo.
Yes, few hairs can be shaved off but half or a complete replacement by the tattoo cannot be accepted. The eyebrows will keep growing back and the tattoo in a few years time will unevenly fade, resulting in a complete disaster.
Asymmetry should be instead approached on both eyebrows and with the right balance. Where hairs is aboundant, it can be slightly shaved off on the opposite, where it is missing it can be replaced by the tattoo.
This method will probably won't make the eyebrows look perfect but the optical illusion created will do its magic!
At EP Feathering Eyebrows when deal with similar cases, I always inform my clients that the sole purpose of Permanent Makeup is to enhance their beauty by smothing imperfections in a natural and subtle manner.