I've wanted to run an Ars game set in a university for a long time. Apprentices goes into detail on the problems with this, notably: 1) Arts must be taught one-on-one and 2) The Gift is antithetical to the classroom environment. Fair enough. Setting aside the Gift problem for now, we are left with the question, "How would you teach the Arts to multiple people at once?" The obvious answer would seem to be a Breakthrough.
What sort of Breakthrough? Not Minor, certainly. Major Breakthroughs focus on Virtues that might be taught. While it is not the ideal solution, a magus might try to solve the teaching problem with a new Hermetic Virtue: Hermetic Teacher. This would allow the magus with the Virtue to teach the Arts to multiple people at once. While potentially transformative, the fact that you have to teach the Virtue means that Hermetic teachers would be rare and the knowledge would spread slowly.
The ideal solution would, of course, be a Hermetic Breakthrough that simply gets rid of the special rule on teaching Arts, and makes Arts work like everything else. Hermetic Breakthoughs state "Nearly anything is possible," and this would seem to qualify. However, a Storyguide who wanted to make this less awesome might decide that, rather than eliminating the restrictions on Teaching, a Hermetic Breakthrough will instead create a new Arcane Ability called Hermetic Teaching, which works just like Traching, but only for the Arts, and can be used to teach multiple people at once.
Set aside the Discovery process for now; lets talk stabilization. individual Sagas will have different rules, but for the sake of discussion, lets presume the Breakthrough requires 60 points to stabilize. Stabilization causes Warping, but if the magus is using a level 15 (magnitude 3) effect, the simple die rolled for this ensures he will never accumulate more than 2 points in a single incident, and so will not risk Twilight on this roll. But, because he needs 60 points and is using only a magnitude 3 effect, he will need to do this 20 times to stabilize the discovery. That's 5 years in the lab and he will be rolling on the Experimentation table each of those seasons. And that roll is a stress roll, and can definitely botch.
Discovery: The discovery process doesn't care about the level of the effect being experimented with. For stabilization purposes we went with level 15 effects and this also lends itself to discovery because such a low level is easily attained in one season of lab work. Every season we can roll on the Experimentation table and our goal is to roll a 10. This gives us the discovery. Assuming the magus has a Magic Theory of 5-10, he can add 1 to this roll, so a 9 is also a success. The magus has a 20% chance of Discovery each season. However, he can also botch, the botch will be occurring in an Aura for extra botch dice, and if he does botch, the +1 to his experimentation also adds to the Disaster roll, making damage to the lab, the magus, the covenant, and Warping points all likely.
Difficulty: This doesn't actually look that hard to me. A lot depends on the dice. The magus needs a 9 or a 10 on the die, and although experimentation botches put him back, or even give him some Warping, the odds are in his favor. He will probably make a Discovery in a couple of years (that would be 8 chances to roll a 9 or 10) but it might take three or four, with bad luck. Once he gets that discovery, he needs 5 years in the lab to stabilize it, and will accumulate more Warping, but never enough to risk Twilight. After Stabilization, he needs to write up his breakthrough and disseminate it through the Order.
Question: Can the statisticians among us figure out, with the assumptions given here, how many Warping Points the magus is likely to accumulate during the discovery and stabilization process? How often will he accumulate enough to risk Twilight? What is the most likely time elapsed for the discovery process?
Would they all wear infrared robes?