Generally, Shake seems to work on Snow Leopard,
although there have been some unconfirmed reports
of UI sluggishness and difficulties with disk flipbooks.
Shake installs some older versions of certain Pro Apps frameworks.
You should install Shake first, then FCS.
Here are some RED/Shake workflows:
http://www.vfxtalk.com/forum/red-lut-shake-t17482.html
www.stuckfootage.com