I think I have the chocolate candy thing figured out!
Chocolate doesn't like liquid. So I break up unsweetened, just cocoa, baking chocolate into small pieces and put in top of double boiler with stevia POWDER. Boil the water under it. Take care not to let steam get into the pot with the chocolate - don't cover it. When it begins to melt, I take it off the heat and stir like mad to melt the rest - and make it be shiny and not lose its temper. (Temper means the cocoa butter is properly attached to the cocoa and doesn't "bloom" in unsightly white streaks on your finished chocolate.)
How much stevia? I liked the results I got with 5 soupspoons of Stevia Plus. Stevia Plus also has inulin, a fiber supplement, which makes it easier to measure - 2 Tablespoons would equal a cup of sugar. Some powdered stevia is just stevia and very very small amounts would be needed.
Yesterday's batch I made some with dried fruit and nuts, some with unsweetened coconut, and some plain, with mint oil. I liked that especially well.