I find the whole note harmonic symbol to be unattractive - kind of a tiled rectangle, as opposed to some type of diamond shape. It’s really the only shape that bothers me, and as a guitarist, I use these a lot. I hit on a simple workaround - perhaps others know this, but I couldn’t find anything on it, so here goes:
–Change the whole note to a half, choose Wide Diamond Notehead
–Engrave Mode, shorten the stem to make it invisible (about -3.5)
–deal with the ensuing rest, either by removing it, or ending the voice at the harmonic.
–do this before finishing the layout, as shortening the stem made some staves move
Much better to the eye. At least, my eyes…