How strict is "one specific spell"?

[Cadd]

This is primarily about the option of locking a focus item to one specific spell (per YS279, getting a free slot on the item), but it can apply to rotes aswell.
How specific would you say these are? Let's use Harry's Shield bracelet as example. If the bracelet is locked to his force shield, can it be used for a spell to extend the duration? If the shield spell is a rote, will the "meta-spell" of extending duration benefit from the rote action? (I'm thinking yes to the focus but no to the rote)

[potestas]

the point of rote spells is they are cast in the same way each time. I have mine set up to inlcude extended duration. If you vary the spell its no longer a rote.

[Sanctaphrax]

I'd probably say yes to the focus and no to the rote, but honestly it's arbitrary. I don't think the book ever lays down the law one way or the other.

[Blackmako]

Can a foci have more than one rote attached to it?

[Sanctaphrax]

I don't see why not.

[Ulfgeir]

A followup-question to this.

Say you have a conviction of 4, (and maybe use a foci on the rote-spell), if you then increased your Conviction to 5, would you then still have the spells at 4 shifts, or could you upgrade your rotespells to 5 shifts?

I can see both sides:
* No, you would be stuck with the lower power of the spell as that was what you learned...
* Yes, it can be uprades, because you are better at using magic you now can utilize your spells more efficiently.

/Ulfgeir

[Haru]

I think you can change your rote spells at a minor milestone. That, of course, includes changing their power.