Hi. To start out, you could read the info on the sidebar, which would lead you to this Starting Percentages. Reddit also has many flavor reviews with percentages. And last, but not least, there are ATF and ELR, which both will give you the average % at which a flavor is used at. I would not just try each one at 2%. Look them up and do the research. It’s the only way to learn. WS-23, for example, is an additive (coolant). Vape it at 2% and most people would get brain freeze, not a good time in my opinion. Good luck.

FLV Mango, Blueberry, Grape 3% FLV Peach 2% CAP Cake Batter 1%

Searching e-liquid-recipes for the majority of them I'd say your safe bet as single flavor would be 2% or less for the actual flavors. Personally on anything menthol I keep it a lot lower like .50 if I just want a hint of cooling. But I think a lot depends on personal preference too, you have to play around with it and figure out what works for you. In my experience a lot of flavors can be tricky, I don't know how long you've been mixing but I've prepared myself to make mistakes and accept defeat when a recipe doesn't work out.