As stated during play, I'll play one of the grogs selected.
I'd also be willing to play one of the grogs. Just waiting to see which grogs go on the adventure.
So we are waiting for Emelric, then, as it is his magus who will make the selection of which grog to bring along, and how to proceed from there. 
Actually, it is much easier to simply cast a forceless (i.e. with 0 penetration) low-level InAn spell at an individual animal. If you don't get information, then you know that this is a creature with Might.
Such a detection spell using T:Smell seems quite strange to me. You are trying to detect a characteristic of creatures around you. You need to target those creatures, thus penetrate their magic resistance. I don't feel comfortable allowing a spell that would grant you a "sense" that needs to penetrate to work. It seems contrary to how sensory-targeted spells are supposed to work.
But in any case, at this point of the story it seems strange to me that you would want to investigate every sheep in every village to determine if one of them is supernatural.
Not to mention that casting spells is pretty obvious and apt to draw attention.
Can I also start a topic where I visit Eule ? Even if that's just a bit later in the story ?
You can use Chapter 2a, which already exists.
Whoa there. I didn't mean to imply that Ludovicus would be casting the spell on every sheep, right in front of villagers. I was trying to come up with a spell that would help him investigate a solid lead, if he found an opportunity to cast it discreetly.
Regarding T:Smell, I was going for something like this, from the Net Wizard's Grimoire http://spellswiki.wikidot.com/intellego-animal:
Scent of Prey
InAn 10
R: Personal, D: Concentration, T: Smell
Allows the receipant to detect the smell of a specific animal, detecting both the animal itself, and its spoor at a range of up to 25 paces.
(Base 3, +1 Conc, +2 Smell)
but using the Sense a magical animal guidelines, and giving it a duration of momentary to just catch a whiff if the purple sheep is among the sheep near Ludovicus when he casts it. I can't tell from what you've written whether you think that sense-target spells do or don't need to penetrate. Working from memory again, don't the rules state that they do have to penetrate? Or when you wrote "Such a spell", were you referring to the forcelessly cast spell you mentioned? That loop hole has always seemed cheap to me, in some applications, this being one. If you were instead referring to the spell that I was trying to come up with, could you please elaborate on where I've made a mistake, or transitioned from just strange to quite strange?
I know you didn't imply that you wanted Ludovicus to cast spells in front of the villagers. My understanding is that you are trying to cast an ongoing spell that will allow him to detect supernatural creatures using smell.
I've just reread the section on magical senses, to refresh my memory of how they work. I don't really like the fact that sense-based spells' magic "radiate" out and try to penetrate the magic resistance of potential targets, but that seems to be how they are supposed to work.
So yes, Ludovicus could cast such a spell. But as you noted yourself, he is unlikely to be able to cast this spell with sufficient penetration for it to be useful.
Yes, so there's no urgency in figuring this out. But looking toward the future, I've given Ludovicus a minor focus in sensing the supernatural, and was planning on having him do so once his Arts are high enough. If that type of magic goes against what you would prefer, then I can find a new minor focus that is still relevant to how I'd like him to develop. I'd like him to become an unofficial Seeker (maybe official at a later time), so there are plenty of other foci that he could find useful. Maybe something else involving Intellego, to aid in exploration and discovery. Like InVi for new vis sources. Just kidding.
I don't have anything against sensing the supernatural when you cast a spell at phenomena, creatures, objects or locations. What I find a bit harder to swallow is the granting of supernatural senses without targeting something other than yourself, but then having that sense have to penetrate against any target that comes within range. It isn't too much of a problem when those targets don't have any sort of magic resistance.
Also, I have some difficulty in determining at what range you should be able to detect something with each sense. Vision based is relatively easy, though if something is weak then how far you would be able to notice it is anyone's guess. But what about smell or hearing? Can you locate a single pawn of vis half a mile away? That's one area where the rules aren't much help.
So your current focus is fine. Just be ready to take spells within its purview with some flexibility.
I guess that's the workaround for sensing insensible creature with Might using Hermetic magic, what with the Limit of Arcane Connections. You can't cast a spell at an unsensed target, so the only way to go is to magically augment your senses to render the target sensible. I don't know how to justify or explain how senses are able to penetrate magic resistance, nor have I seen any explanation in the books. I guess we could come up with our own. Like that the magic resistance of an invisible creature with Might is what prevents its sight species from reaching the maga, and so the maga's magically-augmented sense must penetrate the creature's magic resistance to access those species. But that's just me pulling something from thin air, and it's probably not convincing.
My take is that magical senses are as effective, and affected the same way by the environment, as normal senses. So smelling spells would be subject to wind direction, as stated, and might be enhanced when cast in a room with little ventilation. An invisible creature or object to which the magus doesn't have a clear line of sight would not be detected by a T:Vision spell. I don't think that there is weak-smelling and strong-smelling, or hard-to-see and easy-to-see - if the sense spell is powerful enough to both penetrate and detect a creature based on its Might (using the guidelines I already quoted, for example), and if the environment doesn't interfere with the sense that is magically augmented, then the creature should be sensed. In some cases, a Perception+Awareness roll might be warranted, like if the invisible creature is also actively trying to hide. So, I think the ranges for each sense (except touch and taste, maybe) are fluid, and give the SG some leeway in adjusting their efficacy, depending on the circumstances.
Will Ludovicus only be able to cast sensory spells to detect supernatural targets with no magic resistance then? Other than regio boundaries and vis (the latter of which I'm not claiming as part of Ludovicus' minor focus), what supernatural things don't have magic resistance? Everything with Might has magic resistance. Are there Mightless supernatural creatures? Seems like an paradox.
Yes, Ludovicus will be able to cast sensory spells on supernatural targets, whether they have magic resistance (provided he penetrates) or not. I might be a bit uncomfortable with the idea, but I will stick with how we understand RAW on this.
OK, thank you.
What are the magi's planned seasonal activities for the Summer 1208?
I'll learn Clothe the Naked Form (CrHe 10) + whatever spell I can make in creo Herbam with my total (I caon't remember the aura and lab stats)
Ludovicus would like to study from the Rego summa.
Konrad would like to distill vis from the Aura, just to get that out of the way. He has to do it one season out of four. So it might as well be now.
Boring, I know. But as peregrinator he's gotta pay his way.
Sorry for the lack of responses this week. We have our 3-year-old grandson at home and it doesn't leave me with many opportunities for computer time. I will post sporadically for the next couple of weeks since I am on vacation. But I will post. 
No problem! I know how time-consuming (and fun) 3 year-olds can be. My daughter is that age.