Nice work! Go easy cutting the handle length until you have a chance to use it. Then go slow -- you can't make it longer. (Where have I heard that before?) :gar-La;
I like that shape for a carving mallet. The handles of my favorites are about 1 1/2 the size of the head. I tend to grasp the bottom of the head with thumb and forefinger to use them. For carving, I would perfer a bellied shape handle -- like this () but stretched out.
It's also interesting. I have another heavy wooden mallet (can't remember the wood -- maybe mahogany) that I don't use because the handle is too thin in comparison with the head (and my hand). Tends to cramp my hand and puts uncomfortable pressures on the fingers. I want to convert it by cutting the head down flat on the sides and shaping a more traditional mallet with faces that are flatter while maintaining the angles. I have no idea how it will work, but otherwise it's a worthless piece of wood to me.
Rich