Great question! I've asked a similar one in the Errata/FAQ as a rule of thumb will be useful here.
There are some good thoughts from Jacob (Editor, contributing author on Rivendell supplement) on treating the Magical success as at least an extra 6:
viewtopic.php?f=129&t=8550&hilit=jacob#p64140
"Yeah, it is very important that the narrative impact be appreciated and rewarding. This isn't just the Elf rolls Awareness and the LM answers 'the distant folk are Riders of Rohan' but that the 'the distant folk are Riders of Rohan, 105 in total, with three horses that are riderless, being guided by others. Their spears are very bright but their shields are battered, as if they have recently been in battle. Their leader is very tall. Almost all of them are blond-haired and, though it's hard to tell from here, grim-faced.' That gives a lot more detail, and, more importantly, provides some excellent hints about how a Council might proceed and what questions to ask.
If you have to put a numerical value to it, consider it worth at least one more Tengwar."
But it's also worth thinking about Francesco's reply here:
https://gmshoe.wordpress.com/2022/01/10 ... -one-ring/ - sometimes magical might scare people in a council.
"Magical successes in councils are tricky, as magic isn’t normally welcome in a formal gathering. Men generally disapprove of it, and that would work contrary to a ‘spot rule’ of adding a 6 to the result. I think it’s better handled based on the circumstances, or as a subtle tool, that as you say does not add successes, but ‘unlocks’ more possibilities"
- For my own part, I like having "extra 6" as a basic rule of thumb to make sure these feel special and don't get missed, but also have them "unlock" possibilities as both Francesco + Jacob touch on. Some special things might only be doable with magic etc.
- In your example, I'd lower the healing time by at least a day, potentially healing it outright. [I note Michele has just posted this!]
- You could also have some wounds/maladies that can only be healed by a Magical Result. If the PCs don't have access, getting to the appropriate loremaster character/finding the right item could be a fun and genre appropriate adventure. Aragorn was a skilled healer, but Frodo's Morgul knife wound needed Elrond's Magical result.
- When climbing a cliff as part of a Skill Endeavour by the group, the Elf's magical success allows them to scale the cliff rapidly (multiple successes at the very least, perhaps completing their part of the endeavour on its own). With the elf at the top, I might cut the Resistance by 1 for the others: the Elf helps them up by hand and by rope (if they've got some!). One of the examples in the Star in the Mist touches on this.