As I have continued to practice making a more complex star shape in sculpted glass, I now have the shape I was after: an eight-pointed star with an indent in the center, four large points with a rounded base, and four smaller points between those. When I first tried to make this shape, I was having trouble with evenly connecting the points, to get a smooth transition between the center of the star and the points, and the glass ended up cracking as I was halfway through adding the points. It took a lot more practice, but I had better luck this time. Here is the shape, along with the Voynich Manuscript illustration it is modeled after:

The star shape is still attached to a temporary glass tube that was used to hold it while doing the glassblowing, but that will be removed and a glass-and-metal electrode sealed over the opening. Hopefully I will have the time soon to proceed to the next step of evacuating the inside of the star shape, filling it with inert gases, and lighting it with a glowing blue plasma discharge!

Until then, this was the glass sculpting process of adding the final four star points: