Yes that is possible but only for colors and fonts. The resource names start with Tcm*. In the file $TCM_HOME/lib/Tcm you find the X resources with the settings that are currently used in TCM (but the file is not used by TCM). You can copy this file and adapt it to your wishes. You can load it with xrdb -merge or copy it in your .Xresources or .Xdefaults in your home directory. When you use the xrdb command then it must be issued each time when you restart X.