Another option might be to modify the baud rate of the MIDI interface. MIDI is terribly slow at 1M/32 bps, and most UARTs can go at least 115200. That would also mean changing the baud rate on your PC software at that point in transmission, and would not allow a standard MIDI file to be used.
This was being done over USB midi, which is already faster than standard DIN midi AFAIK. Trying to change the baud rate of DIN midi on both ends of the communication seems like a lot of work.
