As far as I can tell, it should be as simple as picking an instrument of your choice and a volume level on each channel. Keeping in mind the basic musical limitations of the Genesis (5FM channels, 3PSG channels, 1 DAC channel, each monophonic), importing should be simple as long as your module was pre-labeled or specifically composed with these limits in mind. This is what I do when I make midis for import with Sonic QX, and it will give the best possible output. I believe that if someone with only basic knowledge of both the SMPS format and Genesis musical knowledge in general (nineko) can create this program and successfully import several songs into Sonic 1, then anyone who uses a basic reference document (such as my guide) can easily do the same. From what I've heard of the interface so far, the only way it could really be made easier is to add a proper GUI, and perhaps reading initial volume levels in the module. But otherwise, I think that it's fairly straightforward and easy to use as long as you keep your basics in mind.