Please, make usable and harmful runes differentiate in very slight colour diffference, not too big, but just enough to see if you squint. Because it is hard to just guess random rune.
I think the game help before the ritual is misleading some people, I will try and make it more clear.
Here is a hint for gameplay:
The helpful and harmful runes don't ever change, they are hard-coded per demon/per phase.
So hopefully your first few playthroughs you learn and memorize the correct runes for the given demon/phase, then after that you can work on finishing the ritual more quickly to try and get 100%.
Hope that clarifies!