Purely because it is a massive pain to separately increase both ars nouveau and iron's spells and spellbooks mana this mod basically makes it so both mods use same mana pool (ars mana pool)
https://www.curseforge.com/minecraft/mc-mods/mana-unification
#Mod Suggestion: Mana Unification
fresh cloud
fringe hemlock
YES!
quartz coyote
There is also this one for between Ars and Hex
https://www.curseforge.com/minecraft/mc-mods/hex-ars-linker
blazing pollen
the pack already has the hex-ars-linker
quartz coyote
I... I didn't know it, that is a big revelation to me