got my horns installed today, here is how it turned out. I made my own bracket out of a piece of 1/8" steel I had laying around and made my own harness. took around 3.5 hours including waiting for paint to dry and building my harness.
the factory connector can be cut off an old horn and used for the harness, it is just plastic and when you cut/melt away enough plastic there is a nice metal ring that can be soldered too, which is what I did.
there is a cover on the fender to the right of the battery that i removed and mounted my relay there, it should be completely out of the elements in that location.