I'm about to venture into DIY nicquids, and stumbled before I started. I've seen many flavors sold as or with the option of a "Double Shot", but exactly how much are they considering as a double shot? What percentage of flavor are they basing the "Double"? If a recipe says 10% flavor, would 20% flavor(a true double) be correct? I've seen recipes that say 15% flavor, but doubling to 30% seems like an awful lot. At what percentage of flavor is a mix considered "Doubled"? I know mixing your own recipes is honed on personal taste, but I want to get fairly close on the first try without having to toss-n-retry too much.