I did mine using an L bracket that was offered with the horn. It installed very tight and even though you can't see in the pics it doesn't touch anything. There is a bolt I removed under the bike. Make sure to use blue lock tight when you put it back. I installed a relay under the seat to utilize the original wiring. I could not find a way to cleanly run new wires. The original horn relay can not handle the amps but if you go to where that hooks up and add a 30 amp relay in between the original wires can handle the load fine.
What does the L bracket look like......dimensions? I cant make it out in the pictures.