sucralose is a BAD idea! here is a study that shows this molecule decomposes around 125C producing chlorinated byproducts (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4397539/). The boiling point of sucralose is high (669C) and the amount you get doesn’t even contribute to the taste that much unless you overload it; here is another study looking at that:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5624589/
"The present results demonstrate that the perceived sweetness of flavors derives primarily from volatile components of e-liquids that are sensed via retronasal olfaction rather than by taste. Although it was found that the artificial sweetener sucralose can add to the sweetness of flavors, the amount of sweetness added was small and had little effect on flavor liking. "
My advice; if you want a sweet vape use 100% VG mixes or close to it; VG is sweet by itself.
