If its not too late, Id recommend not splitting the cape down the back of he neck, Most taxidermists prefer to mount the capes by pulling them over the form like a sock, much less sewing for them, and less chance of you seeing the nasty looking seam running up the back of the neck. When I cape mine out for the taxidermist, I hang it by the rear legs, and skin it down to the front shoulders, then start working the front shoulders out of the hide without cutting it at all, once the shoulders are almost out, you can remove them and just cut the bone above the knee, and leave the legs on the cape, then just roll the hide on down toward the head, and cut the neck off a few inches below the head of the deer. Then you have the entire hide and cape with NO cuts and the taxidermist has all the hide he needs and can cut it and skin the head however he wants to fit the needs of his work. The extra will be welcomed by the taxidermist, especially if your thinking of having a pedestal mount done, he will need extra length for that style of mount. Here is one of my favorite mounts, it is a full sneak left turn form, and he added a mouthpeice with teeth and tongue, and curled the lips to make it a buck doing a lip curl smelling a hot doe. Hope this helps you out some.
