Dear Max, the second design is cleaner, and I think more versatile. It certainly works for guitar. One suggestion: why not take the central core of the second design, with the circle of lettering and the dark middle, and do an outline (like the guitar outline) for the other instruments (the banjo could maybe be even simpler, just eliminating the guitar outline and extending the neck block). For the a-cappella people, the centre could be a mouth, with an outline of a face. You would then have some continuity for each version, but slight changes -- those simple outlines -- designating each instrument. Yours, Peter