Here's a link to the video I referred to earlier:
http://dollforum.com/forum/viewtopic...562235#p562235, the doll in the video is an original version though and looks a lot softer than you described the custom doll. The video also shows the movable lower jaw, (which I requested from the owner).
Yes, definitely the xtra large boobs might well distort the head size. . . especially when a boob is bigger than the head.