I've been wondering about fiddling with the spring preload on my Ten over the past few weeks, but feel a bit out of my depth. The bike seems to ride softer than it did 12 months ago when new. I've covered nearly 9,000 miles now, so I guess the springs have softened up?

I assume adding a bit of preload to the springs will help things along a bit, but the question is how much. Based on your details I guess I'm looking at additional compression of just 20mm difference between the bike without me on it, and with me on it. (I'm sure it sags far more than this at the moment).