If you check the recipe comments, people who did use it, did at about 0.3%.
I didn’t get any fizz enhancements per se, but mostly because the fizz was already baked in to the cola. The differences are subtle with or without, but the darker, caramelized notes can work with colas. Comparing to WF’s, I’d say similar enough to sub, but the WF had more of a buttery thick nuance to it.