With AM5, the Parma became more formalized. Basically the apprentice is taught most of the ritual, but the last crucial part is withheld. During the apprenticeship it is part of the rules of apprentices that the Master extends his Parma over his apprentice, both to protect the apprentice and prevent the master and apprentice's Gifts from adversely affecting each other. Once the apprentice passes the Gauntlet and is offically a wizard the last bits are taught.
There's an example of this in my online game that I run here at Atlas.
https://forum.atlas-games.com/t/the-stonhenge-tribunal-1222/3507/1
How much you do it of course is up to you, and your idea is a decent one.