Hi Mike,
you didn't say , but if you are using a psr as soundsource for gm midifiles & you have a pc sequencer try changing the bank changes from the default PSR to the GM2 drum sets within the psr
ie
changing

MSB127 to MSB120
LSB000 LSB000
at the beginning of the drum track, this should bring up the GM2 drum sets instead of the psr drum sets.

If you're actually using the psr sequencer to play the midifiles, I don't know how to do it, but I used to be able to access the internal GM2 drumsets in Style Record mode ( they were one level of folders back from the default psr drums in my psr1500.)
Can't see why they wouldn't also be available for sequencer editing mode, onboard.

Hand claps ( Midi note D#1/ Note no. 39) or on the keyboard it's note D#2, appears to be handclaps in most of the psr drumkits including the brushkit.

Wheras in the GM2 Brush Kit it's either a brush tap or a brush slap not sure off hand, which .

Your problem hopefully may be as simple as changing the Bank Change MSB127 to MSB120
in the Drum & Percussion Tracks
best wishes
Rikki