what a good question.
I would say a 10/12 brace would have similar strength to a 12/12 brace based on the shortest side of your 10/12 brace triangle.
For example, a brace based on the 3/4/5 triangle would count as a 45deg brace with 3/3/4.242 sides. I am not an engineer and would be curious to hear an engineer speak on this.