Well, in water, the solubility of sucralose is 283 g/L (20 °C), so you can expect it to be less than that in
e-liquid, especially if you're using VG. I would experiment with putting about 1.5 grams per 10ml PGA or PG if that's the mix your making (as a sweetener, not for actual
e-liquid, that would be ridiculously sweet for an E-Liquid). I prefer to use EZ-Sweetz myself.