I don't want to discourage you from creating your own percussion maps, but I figured it's worth mentioning that Tapspace has already done a lot of this work for you. You can download VDL2 Finale Templates (that contain percussion maps for the majority of complex instruments) for Finale 2003, 2004, 2005 (and the 2005 version will work for Finale 2006).
If you're simply interested in modifying/customizing these percussion maps, you can easily view midi numbers in the percussion mapping editor by clicking the ";listen"; button, then striking the midi key of your preference. Also, I believe Finale allows you to only view ";named"; notes for each map, so you won't have to wade through all the non-used pitches. All mapped notes in the Finale VDL2 templates should have a name.
I have the template already, and was doing as you said by looking at the note numbers for sounds. My issue is that I only really use about a third of the sounds in any given patch, and remembering which sound is assigned to which note when all of them are mapped is a pain. Also, I always have problems with templates that use sharp and flat notes - they never seem to map correctly. I've been using Finale since 2000, and it's still hit or miss with the maps.
One other question - with the full version of Kontact can you remove sounds from a patch so only the sounds I intend to use are loaded? This might help with the RAM problem I'm having.