Tutorial: Sissy bar, Harley-Davidson
Wanting to install a sissy bar to visually complement the rear of the motorcycle, I encountered two main difficulties. The first was the altered turn signals at the rear to which the backrest attaches. The second was the excessive height of the backrest, which protruded higher than the handlebars creating a large gap between the backrest cushion and the passenger seat.
So I came up with an idea to shorten the frame of the backrest by 35 mm and change the way it is fixed - detachable to rigid - under the fender struts. The project turned out to be highly complicated because changing the height and width of the mount (inside rather than outside) required changing all the angles.

In addition, the foot of the mount required welding and modifying the holes for the rear bolts, as well as grinding flat the circular welds that overlapped the fender. The model for the new mount was the factory short backrest from the Wide Glide (#51788-10).

All the work was done by an experienced metal fabrication shop. After receiving it, I spent a few more hours hand-sanding the details and welds before painting. The final step was to paint it black.
Expert words

Always make sure for fitment for your bike’s year and model. Detachable ones are easy to install in most cases. The permanent mounted ones will require to be extra cautious because you can damage paint on your rear fender, so if it's possible protect it with masking tape and use some help because it may be two man job.
Romeo Karpinski, Master Service Technician, Poland