Rick,
There is usually more than one way to skin the proverbial feline. If you aren't worried about stock appearance, this is how I would do it.
Use a horn relay mounted near the horn. Power the relay from the starter switch or some big fat connection off the battery. Use a nice gauge wire...maybe a #10 or #12, and stick a inline fuse in it if you want.
Wire the ground for the relay up through the steering column as it is normally done. This is a relatively small gauge wire...maybe a #14 or even a #16.
Mount the horn somewhere secure and you're all set. Some horns ground through their frame, some have a post that must be wired to ground...I don't know which style you have.
Stuart
