Glen,
Here are the pictures of the supports.
The bases are 22" long, the tops are 8" long and the height is 11". Mark the holes for the tops so that they match the mounting bracket holes and then drill them out slightly over sized to give you a little room for error. I would check the height from the mounts to the bottom of the pan just to make sure that it will be high enough. I have the original style Aviad road race pan on mine. I imagine that the Canton is about the same size, but better to be safe and make sure that the vertical measurement is correct.
Good luck.
Jim