I've been practicing a lot lately making disk beads. Here are some Terra disks I've just posted in my Etsy shop:
Making disk beads is a lot of fun but very challenging. The glass wants to spread out on the mandrel as it's being heated and the thin disk shape tends to become fatter. There are a couple of techniques I'm using to keep them thin. One is using a low flame so as not to overheat the bead and cause it to collapse. I also use the flat surface of my marver along the sides of the bead to keep it in an upright shape. Sometimes I use my mini-mashers and go all around the bead flattening it out. It's usually a combination of all of these things that makes the shape work. I'm still practicing and at times it's very frustrating. When it works out though, I love the results.
Here's another disk bead set, also in my Etsy shop. These are made with a base of Green Ochre and raku frit: