I found the whole knob thing a bit mysterious until a couple of weeks ago (up to that point, I hadn't personally had any problems in 5 years and two RH's). Fact is that the a poor choice was made with the knobs used. They don't simply fall off spontaneously; the tangs (I really need to find out what those are actually called) are very easily damaged. I assume that they've changed knobs, but any unit out there with the older knobs is at risk, if the right kind of stress is put on the knobs. Mine slipped back off of a counter lip and came to rest on the knobs. From dropping about a half inch, with the "impact" shared by all of the knobs, almost all of the knobs suffered at least one bent or broken tang, making them loose. There is no way that incident should have caused any damage whatsoever. With the newer knobs, it wouldn't have been an issue.
Contact TCE, and they will send you a new set of knobs.
A while back, I started a "favorite settings" thread...really dug in and calculated out frequency maps. There was some sharing that went on, but over a bit of time, it became apparent that settings, across the board, are far too individual for sharing specific settings to be of very much value. It can vary so much from bass to bass, cabinet to cabinet, string type/brand to string type/brand, etc. that it's unlikely that you're going to get the same sonic result from taking specific settings from someone posting something like "I set mine to -3, +2, 0, +10".
In terms of really getting a handle on the RH's semi-parametric eq/midpoint functionality, the most valuable thing I've come across was a video someone linked on the RH450 Club thread. The amp used in the video is a Markbass, but the principles apply, and have really allowed me to get the most out of the midpoint setup. The video is in Spanish but subtitled. I posted a Cliff's Notes summary, and the bassist who made the video participated and commented in the thread.
http://www.talkbass.com/bookmarks/1260/view-item