You could get it a bit higher by simply unbolting it from the bracket and moving it up one hole since each side is double bolted. You would only use one bolt on either side then to hold it in and I would use locktite on it! Might get it up an inch or so at least.
I installed a Ultimate backrest on the stock sissy bar on my 1100 silverado. brought the height of the back rest up almost 4 inches. My girlfriend love it. I also went with the ultimate rear seat cushion.
If you go with a different backrest, let me know. I might want to buy your factory backrest for my 950. I was about to buy a aftermarket one, but would prefer Yamaha. Yamaha lists a short and a tall bracket. I don't know which one came on the tourer.
I have the opposite problem ---- my wife and I ride our own bikes so I don't need the backrest and, with a bad back problem, I swing my leg over the back to get on/off so I need to remove the backrest when i pick up my new 950. Here at my dealer in Canada, I'm told the backrest is not modular and removable --- all connected to the saddlebag brackets!! Anybody know more about this??
May be ******* to some of the folks, but for low rent people like me,my brother with a bad back gf, made a much taller backrest for her, plywood + uphoustry, no bull, looks good, used all existing hardware ect. Think on this