Not sure which Gummy Cangy you are referring to; TFA makes two.
According to a recipe forum we are not permitted to refer you to:
Gummy Candy (PG) - The Flavor/Perfumer's Apprentice
Percentages in recipes
Average mixing quantity: 4.7% (Median: 4%)
Minimum used quantity: 0.1%
Maximum used quantity: 20%
Single flavor recommendations: 7
Average quantity: 6.3% (Median: 7.5%)
Minimum used quantity: 2.0%
Maximum used quantity: 10.0%
Gummy Candy - The Flavor/Perfumer's Apprentice
Has been reported to crack/melt plastic tanks. May be fine to vape with glass or stainless steel tanks.
"Gummy Candy" from TPA contains triacetin and can crack plastic tanks. Their "Gummy Candy (PG)" does NOT contain triacetin, and thus does NOT crack tanks.
Percentages in recipes
Average mixing quantity: 4.3% (Median: 4%)
Minimum used quantity: 0%
Maximum used quantity: 40%
Single flavor recommendations: 20
Average quantity: 10% (Median: 10.0%)
Minimum used quantity: 4.0%
Maximum used quantity: 20.0%
I have not personally used either of these versions of TFA's gummy flavors but this might give you a ballpark range to start with.
You also may want to
search this TFA thread and ask you TFA questions there if you don't find your answers. It is a pretty active thread and the folks are very helpful.