Do mages normally protected by the Parma Magica get used to being around other mages like Grogs and companions do?
Or does the fact they cannot feel the influence of the others gift normally because of the parma mean that if their parma is down for some reason they are distressed by the other mage's gift despite having lived with them for several years?
IMS, mages don't get accustomed to each other's Gift because they normally see each other through the lens of the Parma. So normally, magi whose parma is down will reflexively distrust one another per the gift.
I agree with Ramidel: you get accustomed to the negative effects of someone else's Gift, not to his Gift per se. If you do not experience the negative effects (e.g. because you are protected by a Parma), you do not get accustomed to them.
Cathelineau, while I understand where you would go with that idea, it especially contradict all the background of not only the Order of Hermes foundation but also all the other magical traditions from which the greatest weakness is always that they don't have the parma magica to allow collaborative work. They have to use one on one relations (master => apprentice) or letters exchange, which are unefficient in the long run.
Because of the Parma magica, the Order has books, a network, and is the major magical force (known) in the world.
Sahirs for example may have a different form of power, but most of them are ungifted, and they have not the same network relation as magi do have.
Imagine what would be the Order where you only know 1 other gifted individual? what would be the House?
At the contrary, imagine if the Norse wizards would not be hindered by their gift. Their permanent magical runes would combine for every warrior, and the Norse soldiers would get the benefit of each and everyone better rune-power... that is terrifying. I'm not even speaking about the giants gifted found in RM (whose tradition name is currently away from my mind, sorry) whose individual powers are very powerful but their greatest weakness is their loneliness. See Dies Irae for an example of End of the world when a hand of them decide to collaborate! Imagine what ALL of them would do if working as an Order.
Ramidel, I just meant their organisation is far more vertical (cluster > vizir (IIRC) > majlis > grand vizier) than in the Order (magus belongs to House with no formal obedience). I didn't intend to stress which organization was best organized.