Regarding Sugar Cookies, they are a bit tough with TFA only recipes, as TFA does not have a really great solid cookie base, as several other brands have. So, for starters, that's a tough beginning. However, most sugar cookie recipes are not flavor intensive in terms of a lot of different flavorings. I suggest that a good sugar cookie recipe will include the following:
Sugar Cookie
Brown Sugar - 1 - 2%
Belgian Waffle - 1 - 2%
Butter - .5 - 1%
Cotton Candy - 3 - 6%
Sweetener - 2 - 4%
Cinnamon Sugar Cookie - 7%
Cinnamon Spice (rather than cinnamon Danish) - .25 - .5%
Vanilla Swirl - 1 - 2%
I've used several of these same ingredients in the Apple Jacks recipe, but that recipe is also dependent on the dulce de leche, which cannot go in this recipe. I would start with the recipe above and begin to tweak this into a cookie. I know it seems like a lot of sweetener, but you can easily use 10% sweetener with cinnamon's. They work very well together and this won't seem too sweet....at least to me. I do the same in my cinnamon Danish. I would stay away from creams and custards, but at less than 2%, you might find something you like.
In my experience, if I keep the supporting creams and vanillas to less than 5% each, they won't dominate the flavoring. So, in this same way, play with the brown sugar, waffle, vanilla swirl and cinnamon spice to find the right cookie base. The three sweetener flavorings will take care of the rest. You can remove the cinnamon, as well, because you don't typically see this in a sugar cookie. But, a tiny amount will likely make the sugar cookie taste more like a cookie if you use this.
FA makes a very good cookie base - "Cookie". Mixed with a little French vanilla cream, you have a solid cookie....maybe try that, as well. If you go that direction, you could drop the cinnamon sugar cookie completely. In that case, I would use:
Bill's Non-TFA only Sugar Cookie (Starting Recipe)
FA Cookie - 6%
French Vanilla Cream - 3 - 4%
Graham Cracker - 2%
Cotton Candy - 4%
Sweetener - 2%
Brown Sugar 1 - 2%
Butter - 1%
As always, tweak the percentages, and/or add ingredients to suit your individual taste preferences. All recipes must be adjusted to suit your own taste sensibilities and vaping gear, no matter how good they are starting off. I suggest these possible starting solutions as a place for you to begin your own quest on this specific flavoring. There are many ways to mix, and no one way is necessarily better than another. Good luck in your vapeQuest!