The way I read it is "This spell frees victims from enchantments, transmutations, and curses. Break enchantment can reverse even an instantaneous [Transmutation, Enchantment, or Curse] effect. For each such [Instantaneous Enchantment, Transmutation, or Curse] effect, you make a caster level check (1d20 + caster level, maximum +15) against a DC of 11 + caster level of the effect. Success means that the creature is free of the spell, curse, or effect." It was the last thing referenced, and so is the subject of the next thing referencing a previous vague thing.
And, yes, thing is a very precise technical term and has nothing to do with the fact that I am sleep-deprived and fried.
Regardless of the CL check, there's still the one minute casting time. If a fully buffed Cleric can't kill you or force an unbeatable Concentration check to make you lose the spell, then it isn't worth stripping the buffs off him anyway.
Superior Invis before a gank? I am AFB, but does Dweomerkeeper specifically keep the casting time? If not, that works, or you could go Innate Spell with any of a bajillion tricks to raise maximum spell level.