Each manufacturer will recommend a slightly different wattage for their device. Some kits (like the Xros 3 mini and Gotek X) don't have customisable wattage. These kits set the right wattage internally for you when you insert the coil and pod. Some kits, like the Luxe X Pro, offer customisable wattage although they do offer a feature called smart wattage. This feature automatically selects the recommended wattage for the coil and pod you've inserted. You can always adjust the wattage slightly anyway. 50/50 nic salts usually produce the best experience when used at the 10w-25w mark. This is because nic salts generally feature a high quantity of nicotine, which is easy to over consume when too much liquid is made into vapour in one drag. You can vape higher or lower wattage than this "sweet spot", just play around with the wattage to see what gives you the most satisfying experience.