I plan on jumping into DIY very soon and I've been wondering similar stuff about flavorings. The 1st one I wanna make is blueberry & vanilla ice-cream, and I've heard that blueberry flavoring is weak. But I saw on Wizard Labs they have a blueberry "extra" flavoring which must be stronger, and that's the one I'm probably gonna order. As far as percentages, I have no idea at this point, but I was probably gonna start somewhere around 10% total between the 2. I also wanna try and replicate a mountain dew flavor I tried that has a nice sour hit to it, and I'm wondering if this is accomplished w/ the Lorann Tart Sour flavoring. It seems like you just gotta roll your sleeves up and start experimenting, but I hope none of the stuff I end up making is unvapeable lol.