Running the numbers for four covenants I found that books are very expensive compared to enchanted devices. If I were to do more rewriting than a few house rules i'd change the balance of covenant creation points.
Here is the first part of the list for stone bridge caverns
Stone Bridge caverns has items of three types, legacy items from its days as a bastion of hermetic strength and society (mostly reserved for their library, other items have been traded away to accommodate the covenant’s present situation), Items to allow two magi to endure in the covenant without the assistance of covenfolk, and items to defend themselves against a seemingly limitless army of troglodytes.
Plate of sustenance. A golden plate with two effects enchanted into it
• The holder, by twisting the plate in certain ways, can see the market squares in any of three cities. Permanent Arcane connections to the plate have been incorporated into the stonework of these markets. Base 1, +4 range AC, +1 duration concentration, target individual +10 levels unlimited uses level 20
• The plate can teleport some item from the market to the plate base Rego herbam (animal) base 35 (from rego corpus) +1 touch, +1 part,+1 requisite, +3 levels 6x per day level 53
Gate keeper, the tower in the center of the stone bridge is enchanted with a constant effect version of “Shadow of Human Life†which dutifully asks al passersby for tolls on the bridge Cr Im (Me) constant effect level 44
Gate warden, an enchanted arch located in the center of the stone bridge. This is enchanted with a single effect. Anyone who passes through the arch will feel an overwhelming desire to place payment for the toll for the bridge in a toll box (the covenant has conveniently provided one for travelers use).
CrMe base 4, +2 range special (equivalent to voice), +1 duration diameter, target individual +10 levels unlimited uses level 25
Wand of engineering, a wand with two effects used to alter the layout of the caverns and create defensible positions.
• Rock to sand Mu Te base 2, +2 range voice, +1 duration concentration, +1 target part (+2 size) +5 levels item maintains concentration +3 levels 6 uses per day level 28
• Move sand in an unnatural fashion Re Te base 3, +2 range voice, +1 duration concentration, +2 target group +3 levels six uses per day level 23
Tapestry of Warning, a tapestry that hangs in the main hall sewn into the tapestry is a rough and crude (yet beautifully sewn) map of the covenant’s cavern system. The tapestry is enchanted with two effects.
• Detect the intrusion of any human or human like creature into the covenant, all of the creatures that the tapestry detects show up n the sewn threads of the map base 4, +1 range touch, +2 duration sun, +3 target structure (+1 size) +4 levels constant effect +11 levels increased penetration level 50
• Scream whenever an intrusion into the covenant is detected Cr Im level 1 unlimited uses linked trigger level 14
A feather broom for dusting and a floor broom. Both of these items are enchanted to sweep and clean constantly. Note that it is the handles of these implements that are enchanted. The bristles and feathers need replacing fairly frequently. Rego Herbam base 10 +2 duration sun, +4 constant effect level 24 each
Ruby of Fires, a small gem that can be used to create fires that burn in the absence of fuel. CrIg base 5, +1 range touch, +3 duration moon, 4 levels 12 uses per day level 29
A large Abluere Magica as per Covenants p.52 level 15
An enchanted porter as per Covenants p.52 level 15
Four enchanted crossbows. These crossbows are the sentries that guard the covenant, The closest thing that the covenant has left to loyal grogs
• Automatically re-cock when fired ReHe base 3 range personal, duration momentary target individual, +3 levels environmental trigger, +10 unlimited uses per day level 16
• Make a crossbow bolt fly to the crossbow base 3, +3 range of a bow shot voice equivalent with a one magnitude penalty for non-standard range , +3 levels environmental trigger, +10 unlimited uses per day level 23
• Animate the crossbow to move and shoot as directed to by the covenant members. Rego Herbam Base 10, range personal, +2 duration sun, target individual, +1 magnetude item shoots with a skill of 1, +4 levels constant effect, +3 levels environmental trigger (command words) level 31
• Crossbows are as hard as steel MuHe base 4, +2 duration sun 4 levels constant effect level 14