I was looking at the distractions from the lab and something occurred to me.
Does a season in the lab assume a 7 day work week? The reason that I ask is that it occurred to me that any christian mage would have -16 on their lab totals for missing 13 days for sabbath. This especially seems the case for Holy Magus who if they don't keep sabbath, fall into sin and lose their magic.
On different note, would a restriction (prevents spell casting) affect work in the lab?
You did not mention Sunday, but I believe Marko was implying that you should have mentioned it instead of Sabbath.
From everything I know, Jews are supposed not to work on Sabbath. Christians should rest on Sunday, or at least go to church, as mentioned above.
I understand this does not address the meat of the question, just puts it in context.
I suggest you assume that lab projects are bubbling and simmering and so on, but that as long as the holy magus is there in the lab they will proceed without any actual work required on his part. It's the presence of The Gift that keeps things on track, I imagine; the actual work is then abstracted to the other six days of the week. I also like Marko's suggestion that they can leave to attend Mass and then return to preside over the lab afterward.
Good grab, DW - I knew I'd read that somewhere - finding such is always the tough part.
Actually, Covenants suggest exactly the opposite, depending on the Activity. If inventing spells (with our without lab texts), enchanting objects, extracting vis, Familiars, Teaching, possibly others, ongoing spell casting is assumed as part of the process.
However, unless a Divine mage has specific Flaws that state "lab work suffers", I would not make that part of the package. Saturday, Sunday, Jah provide.
If no magic war required during labwork, a non gifted person with knowledge of hermetic theory could easily do the same things that a magus can do in a lab. And that is NOT kosher by any means
But I agree: most projects take you a couple of days/weeks to set up, and then they might be simply boiling. You need to keep an eye on them and make minor adjustments (so you need the Gift) but not much. Far from stressful work. However, not making the adjustments (spending more than 10 days out of the project) mae the final result less perfect. This explanation works specially well for vis extraction and potion brewing, but you get the idea
I suspect that the impetus for having magic be a part of lab work is to prevent an issue with the laboratory personalization rules from arising.
Covenants says that spontaneous magic can not give your lab virtues and flaws. It is implied that spont magic is already taken into account with the character's laboratory total. If this wasn't the case a character could use ceremonial magic to whip up a collection of duration circle or moon spells every season as free enhancements to their laboratory and always collect a boatload of relevant bonuses.