One of my favorite bits of aTweaks is the Scroll Scribing component, and I was bummed that it didn't cover the stuff we added for IWDification. So I made a fork, coded it up, and am awaiting it being merged and released. It was coded to be extensible, so other modders can easily add their own spells.
Essentially, aTweaks will process the cd_mod_scrolls array which is comprised of entries like so:
scroll item file name, level of spell, strref of name => spell file name
The file names are sans extensions, e.g. spwi225 not spwi225.spl. You can generate these however you want; for IWDification the array is built on the fly by an item regexp since all of its scrolls are named CDIAxxx.itm. You can see the added code; I foist the array generation for IWDification into a separate library which gets included if the mod is detected, and then all of this gets processed at the end.
At any rate, I mainly wanted to raise awareness of this so that other mods can add their spell scrolls.