I had some time last night so using the same plasticard stacking technique that I used to make the main "deck" I made two support beams to connect the axles to. I then cut up three tomb king chariots for their axles and stuck them on at measured intervals. It was then a simple matter of attaching the wheels from the chariots to their original axles.
It ended up looking like this.
From here I attached the whole structure to a chariot base and added the Vect slave girls and a few trophies and decorations. I also cut the shape of the actual cauldron out of styrofoam. I plan to cover that with green stuff tonight if I get time.