I don't believe you need to soak it overnight, or really more than a few minutes. There's really very little wicking material, and if you saturate the coil head before you fill it, as recommended, it's ready to go in short order after a restricted primer puff or two. Notice I said saturate, not "lightly pre-soak". Get it wet, put a drop on each of the juice inlets too. Do it just like the big boys do with RDA and RTA builds. Wet. Juicy. Messy even.
It's also a good idea to be sure the juice inlet holes are visible in the chimney crenulations once it's screwed down, just to give displaced air an easier path to the top of the tank.