Im working on some mold designs that will eliminate the dents you put in the mold for alignment. Basically, its almost self aligning. Its like a jigsaw puzzle piece, it will only go together one way. It doesn't require any extra work or effort on my part.
The sprues will be on the bottom of his feet. An area easily sanded. Rather than sink the part into the clay, (when you push the piece into the clay, if it isn't a thick enough part, you can stress the master and even slightly misshapen the part and flaw your mold. Building the clay up and around the master takes more time, but provides a truer mold and better casts. ALSO...pushing the part into the clay makes the part ''stuck'' in the clay. The clay will not want to easily release from the master when you flip it over to make the 2nd half of the mold. You run the risk of the master separating from the freshly poured/cured silicone of the first half of the mold. If this happens an air pocket will develop and fill with silicone when you do the second half. This little film in the air pocket will fall out after a cast or two and the you get a distorted cast.
Building up the bed around the master takes longer but provides for easy clay removal when doing the second half of the mold ensuring the master does not move.
This took me about 5 hours for this half.
I'll post the results after I finish the 2nd half and if it works as well as I hope. The pin in the center isn't needed. After I took the picture I had this idea. I have since removed it.