I use plaster of Paris and Elmer's glue mixture. I also recommend McKenzie Taxidermy part number VOA200, AMB-2, and H1001. I use faux leather I get at Hobby Lobby to wrap it. Just makes it more consistent. I like all my mounts to look the exact same.
Great video, I have watched quit a few so I can learn as much as possible before trying this myself. And your video is one of the best I've seen. You show all the steps and make it easy to follow. Thank you for sharing your techniques.