The shorter the shock the less travel available, and less travel often leads to less comfort. So besides having a possible fender (or fender wiring) rub problem, those 11.5 inch shocks may not ride very well. IMHO it's not worth paying a high price for high end shocks that may wind up causing issues and a poor ride, unless they offer you a money back guarantee if you try them and don't like them.
If you are having issues with getting your feet flat on the ground, the 12 inch shocks will help but they will also come with a trade-off to the comfort level. I've seen reports from several people who bought models that came stock with the 12 inch shocks, reporting that they swapped to the 13 inch shocks for better ride quality. There are other ways to help get your feet on the ground that don't involved suspension compromises, such as seats with a lower and narrower rider section. The Ultra models usually come with the tallest seats, and the sportier models often come with seats with deep rider pockets. Some good riding boots with thick high traction soles are also a good idea for those of us with shorter inseams, and they have the advantage of not causing problems related to short shocks or thinner seats.
JMHO - Jerry