I used to have the HD sissy bar and attached the backrest pad only when I was going to have a passenger. Definitely needed for their comfort, IMO. Then I got the solo seat and said goodbye to passengers, to had the tall sissy bar made. No passengers.

 

With the thickness Of bar I used it would be easy to attach a pad. Drill and tap holes or use a split clamp or some other piece I'd hardware.

 

Quick detatchable HD tall bar

sissy bar with stock HD pad

Sissy bar with a 1982 Honda CB500 pad

 

I added the HD one piece detachable sissy bar on my 72. I'm pretty happy with the look and it will be good if I need to strap a bag on it. I got it online at 20% off so paid just under $200 for the bar and docking hardware.

 

slim fab bar hes on chopcult the bar is welded to the side plates and mounts between the fender and struts sorry i dont have any dimensions.