Increase lab totals by Experimentation (simple die addition?)
Increase Source Quality from studying for vis? (Like Free Study)
For magi with Enduring Magic, would it increase the roll?
Now this would simply skew the numbers higher - you would never get an addition of +11 on an Arcane Experiement (without Extraordinary Risk), but 10 would be more likely.
As best as I can tell, there's no skill level involved in any of these, so I'd think it would apply. I'd only allow a +1 for Vis study, since there's a virtue dedicated to getting a +3 on that roll.
Huh? You can't separate out the die roll from everything else to claim there is no skill involved. You might as well then say everything you roll should benefit immensely from luck. For instance, when I roll a die to add to Stamina+Concentration there is no skill in the die roll.
There is a huge amount of skill level involved here: two Arts and Magic Theory. Generally speaking, that +die is going to be less than a quarter of the total when you include Intelligence, Aura, your lab, and any assistants on top of those three. That makes the random factor a small portion of the whole, meaning this is far more skill than luck.