It makes sense, initially, but keep in mind the shroud on the hammer that serves as a rear sight, is also the shroud that contains cap debris at the moment of detonation! If it is cut down too much, there is the distinct possibility of debris escaping in unwanted directions! This should be considered a risky proposition. I have experimented with two of my pistols. One an 1860 Army and the other a 51 Navy. With the army, I deepened the hammer notch, widening it in the direction I wanted my balls to strike. In addition, I did take the shroud down enough that it no longer made contact with the cylinder, which it did at the very end of the shroud. This allowed me a lower rear sight, but it still contains cap debris. With the deeper sight notch, you have to learn to aim a little differently than you normally would. I find that I lower the front sight into the notch until it is barely visible and now I have proper POI with my balls. With the navy, all I had to do was lower the notch a bit to obtain proper POI.
Dan C