How do you secure your dummy cakes to your turntable to decorate? Mine slide all around since they are so light! When i searched the forums for this answer, i read that someone modified a turntable with a dowel to sick the dummies on but i don't even know what that would look like.
I just use a heavy tape to secure it to a larger cake board and then tape the board to the turn table. Once the cake has set up, then I remove the cake board and stack the dummy to the lower tier. HTH!
I have a cake drum with 3 long screws through it in a triangular pattern near the centre (nails would be better but I didn't have any at the time), pointy end up. Spear your dummy on it and decorate away. You have to prise it off all around with a spatula when you're done.
Do this with a large cake drum, so you can decorate anything from a 6" to a 12" easily.
A wooden base with 3 nails would be ideal, since it's heavier than a drum, though non-slip matting under whatever you end up using will help it not slide around on the turntable.