If you are using the CLI then enter the CLI commands to get you to the point where you would tune the sensor. Then enter the command "show settings".
It will show you the current settings as well as the default entries.
http://www.cisco.com/univercd/cc/td/doc/product/iaabu/csids/csids10/cmdref/15599ch2.htm#wp380148
The same can also be seen through IDM for each signature:
http://www.cisco.com/univercd/cc/td/doc/product/iaabu/csids/csids10/idmiev/swchap3.htm#wp31460
For creating custom signatures the easiest way is to use the Signature Wizard in IDM:
http://www.cisco.com/univercd/cc/td/doc/product/iaabu/csids/csids10/idmiev/swchap3.htm#wp31623
The signature wizard will generally work for over 90% of the types of custom signatures that users generally create.
For the remaining 10% that required advanced settings and parameters not handled by the wizard the user would need to reference the detailed descriptions of the engine parameters:
http://www.cisco.com/univercd/cc/td/doc/product/iaabu/csids/csids10/idmiev/swappa.htm
(Most users dealing with these special types of sigs will post on the Forum are receive help from more experienced users and even signature developers).