Important to place rear wheel at a position equal to full shock spring compression and factor in a fender before placing brace. IE a straight tube across the top of the verticals won't work.
Pretty much a million 1" risers on fleabay. The style with a bottom bolt will allow the easiest mount to the 650 bushing set up if you find and cut bolt ID by 10mm? OD sleeves of the proper length. The stock riser bushings tend to get floppy with age, some extra washers cunningly placed can ameliorate most of that slop while still providing some vibration damping.