I have a customer interested in an upside-down skateboard cake. She saw one online and asked me if I could do it. The cake part is simple enough but I'm wondering how to make the wheel assembly? Do I put supports in it? How do I get the wheels to be perfectly the same size, and for a 1/2 sheet sized skateboard, how do I figure out the right size to make the wheels? I am pretty new to sculpting with fondant/gumpaste and my time is limited so I am looking for the simplest ways to do these things. TIA!

How about donuts as wheels?