Man, that's rough. I love both of these cards so much.
In most Cubes, I'd do Sevinne's Reclamation. Being able to cast spells that get incidentally milled is awesome, and the options expand for what you can grab. In core of the CCC though, I'd do Helping Hand. For a core card, it fits that role better. Power level is much closer, the cost is lower, and the effect is simpler.