You can keep covenants quite short and sweet if your players aren't too fussed.
This is one that the players put together for the Brunnaburgh saga
http://brunnaburgh.pbworks.com/w/page/10215053/Covenant%20Charter
It lists the amount of work expected from the magus, the amount of renumeration in vis, the weight of their votes in council and a few minor other details. Everything else the characters thrashed out in council which was frequently, acrimonious and hugely entertaining. We also had a character who was totally out for himself (Ryce, of house Bjornaer) and who would take every opportunity to come out ahead of every deal. It was great fun.