Just stumbled across this thread.
Windows comes with several .mid files built in that can be used for testing (I already played with one of them and found a difference).
Simply go to:
There's two or three .mid files in the root folder there. Onestop.mid is kind of a default test.
Speaking of, currently when playing onestop and comparing it to MS's GS Synth I noticed that Munt seems to be missing either a channel or a sound (not certain which since I don't have tools to test). The GS Wavetable produces a bell sound in the first few seconds of the file that Munt seems to be missing.
Mods: If this is in the wrong area or needs to be sliced and diced please feel free.