There are 5 flavors that make the Castle Long taste signature.
Acetyl Pyrazine TPA
Brown Sugar TPA
Coconut Extra TPA
Toasted Almond TPA
I have found that subbing each of these cause the recipes "flare" to dwindle the more the flavors get subbed so hence the more the flavor signature fades. I would not recommend subbing any of these or else you're vape experience with this recipe will not be nearly as good. That is my opinion and my own findings.
For me these subs won't work that are listed in his stash,
FA Coconut- Not even close to sub for TFA Coconut Extra, I don't think there is one quite like it.
FA Vanilla Classic- If you have FA Vienna Cream and add .5% to 1% that's the best substitute for Vanillan IMO. The other option here, although you will still lose that signature flavor, is to just use your choice of a Vanilla Bean Ice Cream for all 5 flavors. That's pretty much what the 5 flavors are doing it's a coconut almond milk "vanilla bean ice cream trickery" and it works.
On a final note ,I have made this recipe several different ways and I have made it with FA Brandy but not TFA. TFA Brandy is good but I prefer FA for a closer to Brandy type flavor but I'm sure TFA would be fine in this.