Do we give them each their own workshop? Also do we want to go back and calculate improvements already made for the scribes who have been at the covenant a while? Right now I come up with the following stats:
Amada can copy 12 levels/season with standard quality
Adan can copy 16 levels/season with +1 quality
Nicasi can copy 13 levels per season with standard quality
the hired scribes can copy 11 levels per season with standard quality
Nicasi aided by a hired scribe can copy 16 levels per season with +1 quality
Adan aided by a hired scribe can copy 19 levels per season with +2 quality
If the hired scribes do not have magic theory then using them as assistants makes more sense, since the loss of 8 levels per season is from mundane texts and can be placed into magical texts. If this is the case Amada can copy 15 levels/season aided by a hired scribe, still at standard quality. Note that adan does not know Magic theory in 1234, but from the end of the winter 1235 onward will.
Of course all quantities copied can be tripled with a -1 quality. Thus if a book is split between Adan and Nicasi each aided by a hired scribe they could copy a combined 73 levels per season with +1 quality (Adan would be tripling his copying at the expense of a level of quality from +2)
While some of our scribes have complementary skills such as Illuminator, percamenarius, ink making and book binder, it would be prudent to find specialists in these areas instead of relying on scribes to manage the finishing work, which would greatly reduce their productivity.