Wow.. I've heard of the Billow, but never really paid much attention to it. When looking at it, it looks to be the perfect atomzier for me. I am a big fan of the Goblin and a former fan of the Fogger V4, which are very similar. The billow seems to be what Ive been looking for. A tank you can fill without a screwdriver, doesn't push juice into the channels when you fill, top phillips screws dual coil, slightly raised air intake, and adjustable airflow... I think the V2 (not the V3) will be my next purchase.
I can only give experience from the Goblin... it sounds like a wicking issue. For the goblin I do what Grim Green did for the goblin... I coil and put in the cotton but don't cut it.. insert chimney, then tuck cotton down where it touches the juice well... that's worked for the goblin. I can't say that is what you do for the billow, but it works for a similar goblin.
The end conclusion, is I think it's the wicking. I've been building for a few years, and I know that wicking is the part you can't just learn immediately from a video. It takes some experience and patience. too much cotton, or over wicking leads to dry hits, too little cotton or under wicking leads to a leaking tank. The videos are a godsend to give you an idea, but putting it into practice just takes time and trial and error.