Hm, how about?
- Concert Tour can target another Civ (100% of Tourism goes to that Civ) or be expended in your own lands (in which case 20% of Tourism goes to every Civ)
- Each Concert Tour gives a flat +2 to target Civ, whether that's another Civ or yourself
- Additionally, your first Concert Tour gives you (the Great Musician owner) +1 ;
your second Concert Tour ever gives you +2;
your third, +3, etc.
So even if you don't care about Tourism at all, you might want to invest in Musicians so you can accumulate a lot of Happiness.
Warmongers in particular might be lining up to hire some battle march composers!
Moreover, it has a chance of creating some early- and mid-game balance tension in the Great Musician "Great Work or Tour?" decision; even as a Culture/Tourism-focused Civ, it might occasionally be a better idea to invest in some Happiness at some points in the game if you're not doing so hot in that department.
(Also, I definitely think we should expand the "burning a Cultural GP gets more powerful with more Great Works of that type owned/created" to Great Writers and Artists!)
tl;dr: , , , ...
I don't think we need to make it that complicated. Besides, I doubt anyone would bulb for the 20% to everyone...there is no point. You bulb to beat your strongest cultural opponent, it doesn't matter about the rest.
If you give the happiness to the bulber, than you have all of the strategic decision you need.
1) Should I concert now, giving me happiness but getting very weak tourism
or
2) GWM now, get more culture/tourism....and a stronger bulb later.
Late game is still not a choice, but that is true for many of the bulbs.