Most CZ 75 clones like the Witness and Baby Desert Eagles use robust hammer springs to ensure ignition with milspec ammo. The DA pull can be made lighter by going down a bit on that spring. Depending on the ammo you shoot you might want to go up on the recoil spring, but that may require getting a heavier firing pin return spring.
The smoothness of the DA pull can vary on these guns depending on the exact dimensions of the hammer spring and the hammer strut it fits over. If it is tight then the pull can be notchy as the edges of the strut catch on the inside of the spring. One fix is to round off the corner on the hammer strut.