I have a question about flavoring percentages. I know that it is bit more complex than this, but am I right that the TOTAL percentage of ALL flavorings in a recipe should be...or no more than...15-20%?
As Danny said, it is a Guideline. It depends on How Concentrated the Flavorings is.
I have Read that with some
tobacco Flavors, people are using 3 or 4% Maximum. Whereas a Fruit Flavor might not start to be Flavorful until you Reach 10%.
It's just Very Hard to Say.
A Good Way to get a Ballpark on a Flavor Percentage is to Post the Brand and Flavor you are using and see what type of Range other people are Using. Then take the High and the Low and do some Test Batches.
If the High and Low is say 5% ~ 15%, then you could make some 15ml Test Batches at 5, 7.5, 10, 12.5 and 15%. Then let them All Sit for 3 or 4 days to "Steep".
Then Try each one and see which you Like the Best.