What percentage do you use them at?
Different
vaping hardware in my view requires different flavoring. For instance use of a Clearomizer would require at least 3x the amount of flavoring than an
rba set up with ceramic wicks to get a similar sensation. In the end you have to experiment what is right for you and the device you are using.
I use less than .1% flavoring to get all the taste I like, and in view of the fact many people use as much as 25% of it, my recipe is completely worthless to you. The concentration however is approx. 1.5 to 2 times stronger than most other flavors. So if you use 5% on average, I'd start with 2-3% when it comes to their fruity flavors. But NF has the very best flavoring bar none I have yet come across, and I have tried lots of them. No artificial-tasting flavoring in your mouth, it's the real deal, real blueberry, real cherry.
* Also as a side note if you like fruit flavors, LorAnn makes a natural "Pear" flavor that is just as good, and they don't have much in the way of natural flavoring in their catalogs. I believe it's also 100% organic.