I have made a series of radial circles and have marked each dividing line with a number which I am using for timing, so when one part of the model does something at this point on this cam, something else will happen at the same point on the other cam.
It's a bit messy but hopefully it'll at least give me some idea of how it will all work. I'm going to make the cams out of cardboard first, rather than cut the wood straight away. I also forgot that the cams are turning anti-clockwise so I need to reverse the cut-outs so they move the right way.
Note to self: get cardboard.