GNMIDI has a batch operation to initalize all midi songs with e.g. GM Reset.
GNInsertController can also insert sysex commands (and other commands like controls) to all midi files in a Folder. The insert position can be defined by a rule and reused later to other files.
both programs are at http://www.gnmidi.com
GNMIDI Player has surely settings to play GMReset/GSReset/XGReset/GM2Reset before playing a song automatically and option to adjust volume to a common Level before playing.
Günter