Hi Chromagftw:
I'm probably the best person to answer your question and put you at ease regarding anything rear shock related
For the past few years we have only spec'd "Low" tunes for both compression and rebound on the air shocks that we spec on our products. The first year that the Endorphin was released (late 2007 and into 2008), we spec'd the RP23 with a medium tune, based on what was initially recommended to us. However, we have found that the low spec tune works best and have since about mid-2008, sold RP23s with that tune only.
For the Chilcotin (and Endorphin SL), we will be spec'ing them the same way: low tunes with both the RP23 and the Monarch. One of the great features of the
Four by 4 Linkage is its performance with many different shock options: it is highly shock neutral and very versatile in what shock it can use. Because of the very forgiving suspension curve characteristics we don't need any kind of customized shock setup for any of our frames. The progression curve and other suspension features allow the shock to do its job with minimal interference from any thing else (braking, pedalling, weird suspension leverage curves, etc...). The frame pedals great without needed a lot of low speed compression damping, and the frame linkage also helps control bottom out resistance, so you don't need a lot of help there from the shock either. Our frames can extract maximum performance from factory shock tunes from a variety of shocks, from lightweight air to full on coil: of course, many customers opt for even more specialized performance and have their shocks custom tuned, but of course that is quite often based on personal preference.
I hope that helps!
Cheers,