To test for proper temper dip a small spatula or even a dinner knife into the chocolate until about 2 inches are coated. Allow the excess to drip back into the container. Prop the knife or spatula so it can dry without touching any surfaces. Leave it at room temperature for five minutes if you are using dark chocolate. Now examine it. It should be even in colour with no streaks or spots, glossy but not shiny and when touched does not smear or leave chocolate on your finger. If it meets all these conditions then your chocolate is properly tempered. To learn more about testing for proper temper consider purchasing DVD volume one.
Yes. But you will need to add a decent percentage of fresh, unbloomed chocolate to it to ensure you get a quality product.