Found it:
Maneuvers last one scene by default but those aspects can have duration put on them so they last longer - in fact it specifically uses an example to point out that aspects can be extended...I'll highlight.
system terms that already have a set duration—
maneuvers and stress don’t last beyond a scene,
and consequences remain until enough time has
passed that recovery is possible.
It is possible to set up spells that last a great
deal longer by adding complexity. You can choose
to move the spell’s duration up one step on the
time chart (page 315) starting from an appropriate
default and adding one to the complexity
for every step up you want to go. So a curse that
acts as a maneuver to put Bad Luck on a target
might start from “15 minutes” (about the length
of that particular scene), and you could make it
last all day by adding five shifts of complexity to
the spell. Duration can be applied to a spell in a
flexible sense—how long the energies will hang
around until triggered, how long a particular
effect will last, and so on.
In any case, I wasn't suggesting the aspect last for days. I was suggesting he have the aspect be available for days and only relevant when tagged. Once tagged/invoked, it'd last the scene, then go away.
So here's how I'd do it...then I'll stop arguing the point.
I'd let you start with your basic Lore cap(as if you did a ritual with a complexity under your Lore). 3 shifts to a maneuver, the rest to duration.
Every milestone, I'd get the player to do a couple of declarations to boost the complexity. Basically, reinforcing and making the spell more powerful and last longer.
Every declaration has to make sense for the spell as the wizard is building up and storing more energy. So, in the long run, it's going to be harder to justify making the spell more powerful.
You tag it for a one-shot use. So it'd be an aspect of "stored power" which could be tagged for whatever is appropriate. That aspect could be compelled.
I think it's well within the realm of thaum/ritual.
PS. Good call on the page number!