1150 or 12GSA? If it`s a 12 I got some of the "first time" panniers for £40 & used them in conjunction with an Ortlieb drybag on the back last year for my jolly round Scotland & they were ok. I didn`t expand them on the exhaust side just in case they drooped & burned through. 1300 miles of mostly bumpy twisty roads & they were fine
Search for "Scotland Jolly" for some pics of my bike loaded up. They`re taken quite far from the bike but you`ll get the idea
If it`s for a 1150 I`ve just wasted my time!