What happens in your game is interesting Marko, but I am in a number of other games and this is issue of the rules as written and game in general, not just your saga and its house rules.
My goal is to get my HR's universally accepted by everyone
(evil maniacal laughter)
Besides, I am talking about a HR to begin with.
A cost of double or tripple vis is a huge difference, even in a vis rich saga! In a low vis saga, it has an even more drastic impact.
Yes, this my desired result.
Again, this is my desired result. But the vis cost does make a huge difference, and CrCo30r GToA is still the desired spell to use because it improves multiple wounds. In actual practice, as I have been using this HR for a year now, magi still prefer the higher level ritual with a lower vis cost. Especially when it concerns multiple and more severe wounds.
The HR is not for everyone, I understand this. But for most sagas, I feel it will serve as a valueable improvement to the flow of the game.
There is a spell in Societas that improves a wound by one level. that gets the job done with no house ruling. there are only so many extra little things that I can reasonably expect my players to remember.
That's the spell I am referring too, CrCo30r GToA (abreviated form). It is improving a group of wounds by one level, so I figured improving a single wound one level would be ten levels lower. CrCo20r.
"Heal all wounds" is only one magnitude above "Heal an Incapacitating wound".
This is a special spell of the Leper Mage though. It is possible that it requires the leper magic virtue to be able to use these spells.
Otherwise it is base 25 to improve everything by 1 level. Improve wounds by 1 level isn't anywhere in the guidelines though.
Nope, no special requirements. I know how Mark Shirley designs things. It is not a Mystery, and thus requires no special Virtue. Same goes for his design of the one new spell mastery for the Pralician lineage. Anyone can take it. He said so himself.
Basically, I am taking the guideline of Base 25 to improve all wounds by 1. I call "all wounds" a Group, and extrapolating from that the idea that it requires Base 15 to improve a single wound by one.
No, anyone can use it. It's just one they use a lot, since they are specialist healers. The same is true for most (all?) of the guidelines in Societates - since anyone can join a Societas there are no secrets in their magics.
Mark
Thank you for the verification 
Now, what do you think of my idea of extrapolating that into clling it Base 15 to hea a single wound by 1 level?
Compare the base guideline for "heal an incapacitating wound" and the one for "heall all wounds".
Personally, I wouldn't employ it. On of the things I like about ArM is the close proximity of one's mortality regardless of how much magic you control. If a magus is foolish enough to put himself in a situation where he can get seriously hurt, then he deserves to have a long and difficult recovery without the benefit of a Cure Heavy Wounds spell. Since most non-specialist healers can usually only manage to sort out Light Wounds, the more serious wounds act as object lessons about sticking to wizarding, and allowing the grogs to do the fighting and dying.
But then, that's just my perspective.
Mark
What if :
- non ritual improvement to light wound during, said, sun, at sunset to have all night.
- ritual heal light wound
What happens at sunrise?
Understood. That is a difference in style of play though. I like warrior wizards, like House Flambeau, and I also invest vis in healing grogs.
But aside from the syle of play issue, what do you think about it from a logic-magic theory perspective?