Keep in mind that your MMR is going up when winning, and down if losing. The problem with your strategy of trying to max win points while minimizing losses will result in your MMR growing.
The more a match is worth to you, the less points you lose yielding. The amount you lose also depends on your current score. Until you get high up, I think you should expect to lose about 15 points if a win would give you 25.
You can make an estimate from the point gain figure. 50-N would be close if you’re in high point and probably way less if at the low end. In any case if it shows more than 25 you lose not much and over 40 you lose about 0.