I think it's too much. If I have never tried the taste I checkup how much the vendor tells me to use. Then I take the bottle. Add 4 drops on 5 ml, shake, give it a taste. Not enough, not feeling anything, give it another 4 etc. Then I take the same amount of drops, and measure how much ml this would be, to next time do it with a syringe. I honestly do not care how much a vendor says you need. I learned better less then more a while ago. Overdoing is easy enough, better to start of small
But Flavour art should be in the 3-4% range somewhere. But it might depend on the flavor also, you have overwhelming flavors and normal flavors
I learned with heavey concentrated ones and specially tobaccos to start of with 2 drops on 5 ml