This horns just as good as the level30 horns that add 2 or 3mp and hp since you'll be instrument swapping so often you'll never make use of that added mp.
3CHR is good to swap in for on-monster songs you don't have a +1 instrument specifically for.
only 30 bonecrafting to make a +3 cha horn? Now i remember why i picked this craft... Nice item, especially for a mithra, or other race with naturally low charisma.