How do I substitute a LA brand to a TFA brand?

[Gents]

Wonder Worm Clone
Grape Candy (TPA) 1%
Sweet and Tart (TPA) 0.25%
Watermelon (Clear) (LA) 10%
Cactus (INAWERA) 3%

Can someone explain to me how I change the watermelon clear (LA) to a TPA flavor and still keep the same taste or percentage I have this issue with other flavors too, I heard if it's a different flavor brand the percentages change is this true? and if so what do I need to do? Most of my flavors are TPA is there a calculator or something I can use to change this ?
maybe give me an example I have TPA Watermelon how do I substitute?

 

[Heabob]

I have TPA Watermelon how do I substitute?

I'd try the TFA at the same amount as Watermelon is a mild flavor type IMO.
But you will probably need to make adjustments anyway.
Many seem to prefer the LA version of this one when compared to other brands I've heard/read.
Not sure you'll get the same taste either because a lot of flavors taste somewhat different between brands.
Just have to experiment to find out.