Ah ok, fair enough - that makes sense. I'm currently in the process of moving house so my setup is in shambles but after I've had a crack at E1M3 for this project, I'll see if there's anything I can add to Ofisil's project too. MIDIs are great because I don't need to worry about synth modules or special setups - could even get away with Microsoft GS Wavetable if it's not a performance!
Just out of curiosity, is there a SoundFont or module that you use for GM sounds? I've always found Chorium and FluidR3 to be pretty solid.