Damage recovery is going to be a big deal in this game, and I say that not only because I expect my PCs to get hurt a lot. They will; it's how they roll, but healing is important for another reason entirely. In this party, I have a mage, who naturally knows the heal spell, but I also have a physician. He's an adept with magically boosted medical skills. For this reason, it's important that mundane and magical healing both be powerful options, but that are different, thus allowing both characters to be effective, but in different ways.
I'll start with magical healing. We already know a few things about it: it's focused, since it applies to a specific wound; and it's near instantaneous, since you cast it in combat and see results right away. To make medical healing different, the easiest thing to do would be to invert those traits. This makes medical healing general with a time delay.
So when you cast a heal spell, you pick a specific wound, i.e. one box on the condition track. The successes you generate on your test reduce the box by that amount. If you pick box #3, and you score 3 successes, you heal that wound completely. If you score 2 successes, the wound moves from box 3 to box 1. Thus, using magic to heal someone who's taken a lot of wounds is theoretically possible, but it's an exhausting procedure, since every spell comes with drain. This makes it good for battlefield triage, but poor for long term care.
And that's where medical treatment comes in. Well, almost. In order to figure out how medical treatment would work, I figured I needed to know how someone would heal naturally, and then allow medical treatment to enhance that process. So, for starters, a character recovers a number of points equal to the rating of his Endurance knack every day. Apply this to every wound at once. Effectively, this means at the end of every day, you slide all your damage boxes down a number of spaces equal to your Endurance.
There's a caveat to this, however. You can only heal if you're resting in a location with a lifestyle rating equal to or greater than your highest wound level. Thus, if you were in a low lifestyle apartment (let's call that rating 4), and you had a serious wound (box 8 filled), you would not heal at all. Even if you had damage in boxes 1-4, the 8 would prevent you from healing because you're too badly wounded to recover in such poor conditions.
Here's where the doctoring skill comes in. The doctor makes a roll, and can apply his successes to the lifestyle of the surroundings, which raises them for purposes of healing. Thus, with a trained physician, you could recover from a serious injury in a dirty crash house, but your doctor will need to tend to you throughout that process until you can heal on your own, and each day requires another roll.
As for injuries, they'll require 3 hits on a sorcery test per level. Yes, this means a deadly injury needs 12 hits to be healed. That's intentional. I want injuries to have a serious risk of lingering. You add to your damage bonus considerably by accepting an injury, so there needs to be something in place that prevents their easy removal in combat.
This means my players will be looking at the doctor to treat their injuries most often. Lower level injuries can be treated within a scene or two, but the heavy ones will likely linger for days. I'm thinking of giving each injury a base time and a success threshold for successful treatment. Any additional successes over this threshold can be applied against recovery time, with some minimum time applied per level so a deadly injury isn't negated in an hour because of a fantastic roll. Medically assisted recovery requires only one successful roll, but assumes the physician will be providing treatment the entire time. Interrupting this treatment (say, by separating the physician from his patient) negates the treatment.