
Simply put her and anyone with similar conditions in a weight class based on their muscle mass and not their actual body mass.
Once you do that you will meed separate groups by height/arm length/anything else that is an advantage. Weight class already groups them in a way that avoids completely inbalanced fights based on muscle mass.
Hits to full armor aren’t about cutting through or breaking the armor, but trying to get as hard of a hit as possible. One central outward curve will deflect hits.
Two bulbous curves next to each other will deflect hits on the outside but focus hits on the inner curve into a shape that will ensure all of the power in the hit goes right to the chest. A great way to ensure the wind is knocked out of the wearer.