I also have a fondness for candy bars. Here's a few more I posted a while back:
As you can see, the differences between the candy bars is not that significant. Of the ones I've made, at least, a little peanut butter, or caramel, or coconut or English Toffee can change the flavoring substantially. Notice on one flavoring I use the Kona coffee to provide a special flavoring. Alone, the kona coffee is terrible, but in the right mix in the right context, it works great, just not as single flavoring.
What is interesting is that you can study the differences and pick up nuances about any candy bar. Even my blog on chocolate covered cherries, I accidentally discovered a candy bar about six or seven iterations into the mix. There's enough information here to provide the clues you seek to making your own candy bar to your liking and particular taste preferences. Take a look, and if you still need more information, let me know. I'm happy to help in any way I can. Happy mixing! and Good luck!
Edit: Here's some more chocolates for your consideration....MORE CLUES.....to help you pursue that special flavoring with chocolate. I remember when people used to say that you couldn't make a good chocolate with TFA flavorings! I beg to differ:
Just Plain Ole Milk Chocolate
Double Chocolate - 3%
Milk Chocolate - 7%
Vanilla Swirl - 6%
Bavarian Cream - 4%
Cotton Candy - 6%
Butter - 2%
Chocolate Cream Pie
Milk Chocolate - 5%
Double Chocolate - 4%
Sweetener - 4%
Vanilla Swirl - 5%
Whipped Cream - 3%
Sweet Cream - 3%
Graham Cracker - 6%
Fudge Brownie Sundae
Fudge Brownie - 12%
Vanilla Bean Ice Cream - 5%
French Vanilla Deluxe - 5%
Vanilla Swirl - 3%
Sweetener - 2%
Whipped Cream - 3%
Chocolate Covered Cherries
Double Chocolate - 5%
Milk Chocolate - 5%
Vanilla Swirl - 6%
Bavarian Cream - 4%
Cotton Candy - 6%
Butter - 2%
Cherry (extract) - 1 - 2%
Chocolate Milk Shake
Vanilla Bean Ice Cream - 8%
Cotton Candy - 6%
Milk Chocolate - 5%
Sweet Cream - 4%
Vanilla Swirl - 3%
Double Chocolate - 2%
Butter - 2%
Chocolate Cake
Vanilla Cupcake - 8%
Cotton Candy - 6%
Milk Chocolate - 4%
Bavarian Cream - 4%
Vanilla Swirl - 3%
Double Chocolate - 4%
Butter - 1%
Chocolate Custard
Milk Chocolate - 4%
Double Chocolate - 4%
Vanilla Custard - 5%
Bavarian Cream - 5%
Cotton Candy - 7%
Sweetener - 3%
Vanilla Swirl - 2%
Oreo Cookie/Cookies and Cream
FW Cookies and Cream - 7%
Sweet Cream - 8%
Sweetener - 5%
Double Chocolate - 3%
Vanilla Swirl - 3%
Bittersweet Chocolate - 2%
Bavarian Cream - 2%
Look through the list and maybe even make one or two and see if it suits you. No point in re-inventing the wheel right out of the gate. If you have an idea about a flavor combination to add/change the butterfinger, let me know and we can strategize on it together. As you can see, I do love my chocolate and have spent a lot of time developing recipes for it. Since peanut butter IS the primary in the butterfinger recipe, we may have to go a different direction, as there is very little chocolate in that mix (because peanut butter is the primary). Make sense? Anyway, Good luck!