Look for Jerry Kuhnhausen's books on the Colt Automatic.
The sear notch can be made shallower, but be careful that you don't make it so short that the sear strikes the half cock notch hook on the hammer's way down. You can bevel and/or radius the top surface of the half cock hook to help push the sear nose over it as it passes by.
The other modification is to put a SMALL 45 degree chamfer on the rear edge of the sear, effectively moving the mating surface forward, shortening the creep.
Also, reduce the free travel on the trigger by tweaking the sear engaging surface at the back of the loop, if necessary.