I found the vape to produce less vapor and a "harsher" TH, and less vapor. I don't vape silica in parallel because of this reason.
I X My silica (doubled up) when I use silica. I even X my cotton (doubled up) when I do cotton. The air is forced into toe coil head on as opposed to letting some graze.
Think taking genesis style and turning the air hole off center here if you've ever used gennies).
The only parallel I do is a triple wick cotton. But that's because the triple closes the gap even more.