On the plus side, my vendor (Old Britts) is allowing me to return the standard size rings (new and unused in original boxes) for credit. Thank you Fred and Ella!
Still struggling to get the carbon off the heads. Single bladed razor took off the "chunkage," but the rest is resisting. Have soaked in SeaFoam, brake cleaner, water, and now mineral spirits, trying to soften it, but so far no joy.
I'll not be stymied, though, one way or another!