There’s a way to do it fairly well currently already. By measuring the approximate distance from the touch point to the desired exit and inserting the resulting value into the LDA dialog box that should automatically populate when you choose the airport and runway. By this means it will give you the braking needed for the inserted distance as well as the landing distance achieved with said braking intensity (or in an extreme case will report that no stopping will be achievable within that distance even with full manual braking).