I'm not sure how SCH accuracy requirements are different from WHM accuracy requirements if both are aiming for 100% accuracy on all spells (including Miasma, Energy Drain, and Aero). I don't think a SCH can do 10% with uncapped accuracy even with auto-hitting DoTs, but would like to be proven wrong in this respect.
You'll want a fully ACC melded relic, three pieces of gear melded with accuracy, and food for capped T13 for either if you have any real intention of doing DPS as a healer with 100% or near 100% accuracy.
Random edit: Just one more point, if you ABSOLUTELY WANT TO MAXIMIZE SCH DPS you might make the argument to get SCH accuracy high enough for Flank Accuracy so you can auto-attack book while using Ruin II. . . ( which means SCH has a higher ACC requirement than WHM in some twisted convoluted way )