If your using ART2 or mega voices in your piece. He will not get the same effect. He has to have the exact same patches (a GENOS also). Mega voices use different velocities to trigger different samples, as well as some very high notes C6 octave to trigger Genos to make changes to sound.
Yes, MIDI is data only, no sound, it tells the host to play a certain note, with a stated velocity at a specific time.. With some effort, you can modify the midi files of specific tracks to work with a different instrument.
The positive easiest thing, would be to stick to the standard MIDI programs. Not using MSB/LSB banks.. All MIDI instruments will respond correctly to the original 128 programs. So the Strings sound from your Genos, might not sound the same. but it will be a close approximation.