Norm Soucy makes a 1 1/2" lowering Rocket hat will work perfectly with your C-14 shock.
I used one when I did mine...
Look for it on the COG Forum, and do a search for Norm Soucy.
Here is 1 discussion. There are many about installing different shocks on a C-10.
http://forum.cog-online.org/tiressuspension-c10/twitchy-tires/msg616068/#msg616068Ride safe, Ted