I'm designing a setting, likely for a Savage Worlds game, and I want to ask for some input.

Fantasy world, roughly 1920s tech level. Every person has magic, to a point--for the vast majority, it's so small they barely even notice, except in the way that violinist can really make her instrument -sing-, y'know?

Some people are born as thaumaturges, wonder-workers, people whose magic is far, far above normal people. They seem to be able to call "spirits" from the world, even from inanimate objects, and make them do their bidding. Nobody's really sure if these spirits were always there, or if the thaumaturges' magic literally makes things come to life. Big, flashy displays of power, like lightning bolts and fireballs, are incredibly rare; magical healing requires herbs and a ritual; for the most part, magic is very subtle, but still powerful. Holding your body in such a way that you're unnoticeable unless someone is looking for you specifically. Slightly influencing a preexisting flame, or changing the wind direction. Magically making wood bend -just right- for the perfect acoustics when you're making a cello.

This will largely be an "adventure-based" game, a sort of Jazz Age urban fantasy. How can I best represent magic like that mechanically without making it useless for adventurers? I've leaned towards Savage Worlds because it seems to have a nice blend of simplicity and adventurous sensibilities, but I'm open to other systems.