Thanks for the info Reelthing.
Should have read a couple of other posts first.
After reading on in this thread, bentwheel had a "link" for the horn he used and recommends.
I found on that web site how to wire up the horn they sell. Looks like it comes bundled with a relay with the proper specs. etc. so it's just a matter of fabricating the mount and following their instructions.
SavageRider