pancho first let me say some of the custom hammer makers are using 1045 (Low Medium carbon steel) that is what they were taught to use. Not the best hammer steel. And then there is the divided with a fuller face from the Eye.Again it is a style. No real benefit. You can only hit with a hammer 5 ways Flat on the face with the toe of the face the heel of the face and the right and left cheek. type of hammer makes no difference you can use the same method of hammering with any style hammer. cross peen, Swedish, ball peen, Hofi hammer different hammers for different jobs. Its is the one that helps you get the job done.
I am a big believer of just do it get some mild steel and do it 10 times you will get a better understanding of it do it 100 times and you find an easier way of doing it. Type in Francis Cole blacksmith on you tube I have put up videos that will help you