@ElZorro
If your MIDI hardware is anything like mine, you probably have bank MSB / bank LSB messages you can send for a particular channel to select a variation on one of your basic GM sounds.
Alternatively, your hardware might allow NPRN bank selection, though I've never seen it implemeneted.
To be honest, I'm so lazy in that regard I tend to set up everything the way I want it on the hardware, then dump it to octamed and save it as part of the module.