Dont forget the rotation of the wheel will naturally pull the post back in toward the rim as the brake is applied. Maybe with hydraulics there is a more braking force involved so a bit of extra strength is definately beneficial. I cant see you braking the posts though. How hard do you need to apply the rear brake, are you doing trials on this bike or just riding trails?
Not trying to make you wrong, just saying ditch the brace, save a few grams, and dont worry about it. Its just my 2 penneth worth...