Well, I tend to pick background options for my characters for flavour and story potential, trusting the storyteller to make things interesting and balanced between the characters and the challenges. I'm not interested in powergaming - not only is it essentially pointless (the storyteller always wins if s/he wants to), it's also inelegant. Some of the sagas on the forums here have characters with multiple magical puissances / affinities stacked with Int 5. Bleh.
Secondary Insight was chosen to represent the idea that he's intelligent, a good student - but not focused. He's essentially seeing magic as a fairly uniform thing instead of a collection of seperate schools; spells are the re-weaving (re-sculpting) of Creation, which is also why he has the glaring weakness at Perdo - he can't bring himself to directly unravel Creation. I admit that it looked weak - I'll have to think on what to replace it with. I don't want to be the Tribunal's smartest man, so Int 5 isn't really an option. A Puissance for Magic Theory seems powerful but boring (and it doesn't fit all that well with his paradigm, which is slightly off for an Hermetic mage). Maybe some kind of Relic (likely a book or collection of scrolls)? Not sure yet.
The idea behind Tethered Magic is that he makes items that are essentially vessels for spells, prepared in advance in his workshop (lab) but applied in situ. With Tethered Magic he can create a variety of protection- and boost-items, hand them to others, and have them maintain the spells - saves a lot on Concentration, I figured. Imagine half a dozen grogs with Wizard's Sidestep available without a need for a Mage to babysit them. Of course, it would only work with people he could train in the use of them. Still, it seems suitable and useful.
Note, that really nasty things could be done with a strong Guile / Charm score and Tethered Magic. Just got to be real careful about that arcane connection that could be traced back, should people investigate. This isn't my plan for Carduelis, but I noticed the potential for more than a little mischief or mayhem.
As far as the Ward goes - I assume his ReVi total will go up soon enough, so that shouldn't be all that much of a problem Then again, there's a lot of interesting spells that could protect a campsite - I'll pick another. Maybe I should device an alarm spell. InVi would detect demons and mages, I assume, but what would detect a fairie or divine creature?