So, I spent the weekend wrestling with the Silurian again. I finally mustered up the courage to start molding the cast, and I worked on that pretty much the entire time. It was definitely a learning experience, and took a lot more cement than I had anticipated, so I was glad that I had purchased the 100 pound bag instead of one of the smaller containers that you usually find online! Unfortunately, I was so wrapped up in it (and I was usually covered in cement slurry), that I didn't remember to take pictures of the process.
I cracked open the mold yesterday, and it went pretty well. There seem to be very few air bubbles, but I still have a great deal of clay to clean out of the mold. The front half of the mold did decide that it wanted to be two separate parts instead of one, and cracked down the thinnest part of the cement, where the top of the the center crest was, but it was a clean break, so it shouldn't be too hard to fix. I kind of figured it might happen, so I wasn't entirely devastated.
I did take a picture after I cracked the mold, so here's a pic of some chaos!
Now to clean out the clay...