I've been using this handlebar for a year, I'm impressed with this one!Yes, you would need to change the cables for 12", one of my friends has changed and added this handlebar "https://www.vikingbags.com/products...for-harley-street-glide-flhx-s-st-matte-black", and he changed the cables.
I have been riding it myself and was impressed by the quality of the handlebars. The first time I tried them, they went clean with no struggle and provided me with the reach that I desired. I have operated other brands in the past, and these have also been good, but they did better than I had anticipated. Some of them are secure with stock cables on a Street Glide 12s; others replace them because they have to. It makes no difference; a good set of bars really makes the difference in the feel of the bike.I've been using this handlebar for a year, I'm impressed with this one!