Had them on my softail that i use for 2-up touring at full load. Too soft, bottom out frequently, shipped them to Progressive, came back as OK.......
I ordered a set of AirTail for $525 (without the on board compressor) and we'll see how it goes come spring. I assume that they have a lot more option to set damping and preload than the 413s.
Good luck and do a search on 413 on the forum. Lots of opinions......