HMRE says they learn and cast in the same basic way.
It explains how they use Vis, which is helpful, but can they use other options such as gestures/voice, ceremonial magic and spell/charm mastery?
I would say no for spell mastery. The Gruagachan in the same book have explicit rules on spell mastery, the lack of this suggests it may not be important for the learned magician tradtion. Also, as charms are super-specific (differents ones exist to heal a slash to an arm versus healing an arrow puncture wound to an arm) they are too narrow to justify spell mastery.
Gestures/voice - as they are cast "in the same basic manner" I'm sure gestures/voice apply to casting charms, and don't affect amulets or chartae.
Ceremonial magic - as charms are supposed to be cast very quickly and have limited duration, I think ceremonial casting is against the general idea of a quickly recited charm, but theoretically there's no reason why a learned mage wouldn't carefully compute the astrological influences and anything that might affect the spell, so ceremonial casting should be possible - but if you've got 15 minutes per magnitude, you may as well spend a few hours creating a charta.
Thanks for the response. Good point about Gruagachan.
Specialising in a charm does seem a bit strange when they are meant to be pretty specific.
The allowable Hermetic Virtue list for Learned Magicians in HMRE includes both Quiet and Subtle Magic.
As a sort of follow up question:
Since you get a bonus on chartae/amulets for similar charms, it'd make sense to learn a charm that matches a common effect.
Learning charms has you multiply your lab total by five for charms, is there a limit for how high a level charm I could learn?
I guess it's meant for learning many charms at once, but a high level (say like 50), and impractical to cast, Revive the Fading Amulet could allow for a large useful similar spells bonus to making a charta that does the same effect.
The major limits are the restrictions on how similar a spell needs to be to get a similar spell bonus, and the fact the really cool targets and durations belong to amulets and chartae rather than charms. You can research a general guideline as high as you like, and use the bonus in the lab if it's otherwise similar enough.
Using a charta to revive the fading amulet is time-consuming compared to having a usable charm (hours as opposed to a few seconds), and any similar spell bonus you get will only add half the bonus to the highest level of charta available, so you'd be spending a season to give yourself a modest boost - and that's IF your SG doesn't house rule this as undoable, as Succurro Magicam effects are the one most likely to be house ruled in my experience (and looking at this board, a good few other people's sagas).
Good points.
The character in question doesn't have "Strong Verbal Charms" as I didn't want to step on the mages toes, in regards to throwing magic around powerfully, flexibly and quickly.
So even though it's a bit wasteful, it'll probably help enough.