What is the best position for mudguard in cycle
With a hardtail like that you can fit a full rear mudguard that covers much more of the tyre, especially towards the back of the wheel, and covers it more closely With what you've got you're never going to keep your back from getting splashed. You can experiment with the angle and height to see if you can get a little better, but I doubt it's worth it. Those mudguards will keep the worst of the mud off your (lower) back but that's about all - fine drops of water  get everywhere and soon soak you.