Help with magic system: learning from reality

Hi! im making a fantasy *world hack, and im having a little trouble with the magic system.

In my world, magic is cast by playing "songs". All classes have a magical song among their move list (night vision, duplicate self, aura of silence, healing, unmaking, etc...). This songs are cast on targets by singing (rolling +cha), or enchanting objects by writing the runic transcription (rolling +wis).

The trouble comes here: in the fiction, outside the rigged songs that are learnt traditionally depending by your class, there are two classes that can compose their own songs: The musician and The weaver (because this guilds are the ones that composed all the known songs) The idea is that they can cast songs by using their own personal experiences as an inspiration, or any song they've listened closely enough to catch its "core". But i don't know how to represent this mechanically.

i've planned three options:

1: making a "song catching" move: When you are exposed to a song's effects (a singer) or a song source (a twister may carry a "spinning" song) roll +wis. On a hit, you learn the song (your MC will tell you its effects) and add it to your moves.
why i don't like it? Because i feel that it would drag the game, and i dont know if its right to have some players chasing owls in the forest in order to learn "night vision"; also its too abstract to work correctly (how does one learn to deflect bullets? by exposing yourself to a kevlar vest?)

2: instead of learning the song a priori, you can describe it a posteriori:  you can use any song you want (describe it's effects) if you retroactivelly tell the MC what event of your life you use as inspiration. You roll +Cha or +Wis as usual if you either sing or write the song.
why i don't like it? because i feel its too OP, as the players can exploit this indefinitely. They can play a song of dismembering just by telling the MC that they teared a flower's petals when they were young. However, i feel that this move could work if i could manage some boundaries. Any suggestions?

3 you can learn a song whenever you level up. You can pick an existing song from your class traditions, or a made up one if you explain where did you learn it.
Why i don't like it? because i think its boring. However, it feels like the most sensible option.


Any opinions or ideas about this? Thank you in advance. I can answer any questions if you need any context for it. The hack itself is very high on magic, and is inspired by the videogame Loom, some good old nordic myths and the Adventure Time TV series. 

How about giving those classes some variation on the Workshop moves, that they can use to write songs of their liking? This draws a strong line between composition and performance/improvisation, allowing them access to the former through a more deliberate process. The latter could be represented through less powerful moves, while still supporting the fictional idea that these are the same sort of people who composed the 'traditional' songs everyone uses.

This sort of approach passes a lot of the responsibility to the MC, in terms of figuring out how songcraft and magic work in their world -- but this is a pretty standard AW thing to do (see The Psychic Maelstrom/open your brain, for example.) But you would also of course write a series of song/magic-specific workshop questions/obstacles/etc. that could guide the sort of things that seem appropriate (like 'you must be exposed to a similar effect, or similar song' or 'you must find a thing in nature that sings the song in question' or whatever.)

The workshop moves are the go-to tech for 'a class that can invent stuff' -- I see no reason why they wouldn't fit in this case as well.

thank you for your help! i've taken this option at least provisionally; i like it.

Forgive me for being a little off topic, but your premise reminds me of the 8-book Spellsinger series of fantasy novels by Alan Dean Foster, although I'd guess you'll handle it a little more seriously than he did. As a teenager, I loved the series though. :)