You only need one file, unless you're using Hidden Effects which need one of the main files to go with.
The affected spells are: Bless, Curse, Peace of Mind, Haste, Armour of Frost, Fortify, Fire Whip, Soul Mate, Farsight, Flay Skin, Vampiric Hunger, Bleed Fire, Decaying Touch, Shackles of Pain, Corrupted Blade, Elemental Arrowheads, Erratic Wisp, Infect, Master Of Sparks, Peck, Spirit Vision, Favourable Wind, Blinding Radiance, Play Dead, Levitate, Encourage, Deafening Shriek, Deflective Barrier, Guardian Angel, Thick of the fight, Summon Inner Demon, Flaming Tongues, Demonic Tutelage, Soothing Cold, Firebrand, Vacuum Aura, Mend Metal, Bone Cage, Siphon Poison, Sparking Swings, Vampiric Hunger Aura, Breathing Bubble, Mass Breathing Bubbles, Venom Coating, Venomous Aura, Throw Dust, Dust Blast and Glitter Dust. (48)
I didn't change Polymorph, because there's already a mod for that. I didn't change some statuses in order to keep the fun in the game, for example Dominate Mind, Living on the Edge and Crippling Blow.
You can find the box containing the Cancel skillbooks near the Braccus Rex statue waypoint on the Fort Joy Beach, near one of the fast travel boats on Lady Vengeance, and near the starting waypoint in Arx.

  Changelog:
 v1.2.2:
- Added in Farsight to main files.
- Made optional files containing only specific skill changes.
 v1.3:
- Added more skills, including offensive types.
- Added Cancel skillbooks.
- Added optional files that remove the status effect visuals.