I have them. They are better than stock and they don't "bull buck" like the OEM shocks did. Where I live there is a lot of twisties and mountain roads so I can tell you I have put these shocks to the test. The key is that I adjust preload based on where I'm going and how much weight will be on the bike. If that wasn't done I'm sure the shocks would respond awkwardly. Sure that's true for any shock.
Just a little side note. If you purchase these shocks I have found a trick when adjusting the shock that makes it easier. When turning the top cap of the shock for adjustment reach down and turn the spring as well...... this makes turning the top cap much easier. The more preload that is applied the harder it is to turn another words.
I like them..... they aren't the best shock that could be installed (Wilbers) but it made my ride more enjoyable.
Pop in to Revs Racing Halesowen ,sorted my Rocket with some Wilbers rear shocks and front springs ,transformed the bike ,rear shocks slightly over stock length (1"(25mm) lifts the rear up slightly and improves ground clearence and stearing.
I would say NO to the 11.5" (1" shorter than stock).
If you are a very easy rider, you could perhaps get away with it, but the rear fender wiring will be in danger from the tire.