sf2cfg sffilename [> cfgname]
sf2cfg is a utility program which constructs a gt configure file, with a list of instrument patch names by bank, for an AWE SoundFont file. Just give it the name of the SoundFont file, either an old style .sbk font or a .sf1 or .sf2 font. Capture the output in a file, edit it if you want, then edit gt's main configure file (timidity.cfg) to refer to the new cfg file by adding, e.g., lines:
(derivatively) Copyright (C) 1998 Takashi Iwai
Greg Lee <firstname.lastname@example.org>
adapted from a program by Takashi Iwai.