I've used quad coils in a couple ways, I have a Kennedy clone that I set you nice big coils over each of the air holes, and my Lord does it CLOUD! it's a nice vape, but it also gets hot real fast! That may just be due to the cheap nature of the clone, but it is hot. I can only get about 5-6 (giant) rips before I need to let it cool. The other thing I'll say about that particular setup is that it's harder to wick, and it does suck down the juice.
I've also used parallel coils which is kind of like quad coils, more surface are/lower resistance.. I really didn't care for it too much... The only time I think I'll revisit parallel coils is either when I'm doing a Zipper coil, or some other coil where looks are a factor.
I've never done vertical or horizontal barrels, Though I might do a horizontal double barrel on my velocity clone too just to see what it's like. I think I'd only do a vertical double barrel on something with a bottom feed air flow where the draw pulls across the biggest surface area of coil. That's not sciences just philosophizing...
I enjoy playing with these things, I suggest giving it a shot and seeing what you like! Its all about personal preference my fellow vapist!
