Yeah, healing magic is a bit of a weird topic. In the novels, it's suggested that actually removing wounds and such (consequences) is an act of incredibly high power. Anything that wizards do appears to be the sort of thing that substitutes for a really good medical attention roll (ala Scholarship), so I'd mainly think in terms of roll simulation for starters.
To actually REMOVE consequences... well that's some deep magic that borders on "transforming another", Law territory. I think that I'd probably make it take as much effort (or close to as much effort) as it would to transform someone (which is usually priced on "what would it take to kill them?") but I'm a hard-ass for the canon details.
If you wanna go for a more lightweight calculation, figure out how many shifts it would take to *inflict* the consequence if the character's stress and consequence tracks were completely empty, and maybe use that as a guideline.