two wax toilet rings?
I agree with purchasing a flange extender. They are about $5 at Home Centers. Using two wax seals can cause more problems than they solve. If the top one slides while installing the toilet, you could block the discharge of the toilet. Even the thicker wax seal would be better than two seals. Problem I see is that the more area you span with a wax seal, the more likely it is to fail. Should you need to plunge the toilet, you could break the seal.
If you have never made a mistake, you haven't done much.