If your tractor has a loader or remote valve, you need to set all the valves the same, as the lowest relief valve upstream will do all the relieving.
You also need to stay within the tractor psi specs or you take your chances.
Say your loader relief is set to 2650 pso. and you set your 3pt relief to 3000. Guess which relief valve will relieve if you overload the 3pt.
The loader valve will set your limits in this case.