Suggestion though - offer a switch for Rock vs Jazz so that Rock gives sharps and Jazz the flats. That may help woth clearing the layout a little. Actually it's not that simple really but it may do.

If you really want some fun with music theory you need to learn "The circle of fifths". This is a great tool to work out number of incidentals, the fourth and fifth to the root, relative minors and will all fit onto a single piece of paper.