You'll get some founding gift from each Rhine tribunal covenant - negotation and side deals may improve these.
For Durenmar: You automatically get an Aegis casting tablet or lab notes (you can choose any level up to 50, but there are vis costs to be paid) and one season that you personally get to spend int he Great Library each and keep what you copy all rights included - ideally we can copy one or two of the best summae and trade from there. If you can send substitutes will we a matter of bargaining. The gift from Durenamr is incredibly valuable because copies from it can be traded for other good books later.
You may want to contact the other covenants to coordinate the gifts you get. That requires letter writing or travelling.