Removing Spells from the Priest Spellbook.

I'm working on a couple of Cleric and Druid kits that use completely their own spells. Where a series of new "School" values are created to make way for 2ed's Priest Sphere concept. So all current priest spells will be redone to be classified under the Spheres instead of the Wizard Schools.

I've created the new spells and I can add them to the priest spellbook but I need to be able to remove the Vanilla spells from the priest spellbook to avoid having duplicates.

I initially tried applying a .spl file to the kit's .2da file with the "Removal: Remove School [220]" effect. Where I tried to remove all schools (Necromancy, Abjuration, etc...) and therefore all of the Vanilla spells in one go since they are listed under that school. But that didn't work.

I then tried the effect "Spell: Remove Spell [172] where I would target specific priest spells to be removed from the Spellbook. But it wouldn't remove any spell I specified.

I then tried to find a copy of CLABMA02-CLABMA09 to see how BG1 restricted access to Schools. With the idea to copy whatever they did. But that is unavailable for extraction.

Either somehow the priest spellbook is untouchable or I'm doing this wrong. I tried other Priest Spellbook specific effects like "Spell: Disable Spell Casting Abilities [145]" where I tried disabling the entire Priest Spellbook but that didn't work. I tried doing the same to the Bard's spellbook but it didn't do anything either.

I have no trouble applying .spl files with non-spellbook related effects, but anything related to the spellbook is causing me troubles.

Quick Question... is it possible to remove spells from the priest spellbook?

If so, then I'll post screen captures of the .spl and .eff file setup as it appears in DLTC to get into the specifics of what I'm doing wrong.