I used to use a Kraken with a horizontal coil setup. I liked it because I didn't have to fiddle with air flow rings (much) or unscrewing. I just pull the top off, whip out the cotton, dry burn, insert next cotton, and wet it down with the next flavor. Now I have
one of these on the way. Still the same pull off top and I can keep my Kraken to use as the admirable tank that it is. I took a bit of a risk ordering it as it is so small, and no
reviews but it's only $5 and let's face it, when it comes to drippers, there is only so much that you can do differently. The principle is the same regardless (and I have a drill press and a a thousand bits to enable me to play with the airflow, should I need it.
One thing I do when testing flavors in a dripper is I make a short wick and I don't cut off the tapered ends (cotton ball wick material). Instead, I twist them together over the top of the coil so the
juice runs down both sides pretty equally and meets in the middle of the coil. Kind of a teardrop shape. Just a few drops and you're ready to taste your creation with minimal waste (should you find the need to adjust it.
In any case, one of the hardest lessons for me to learn with DIY has been to not get hung up on the % of flavor. Just because one (or 50) people never need to go above 10%, doesn't mean that my dead taste buds will detect anything more than the most trace essence of the flavor at that level. Embrace the beauty of DIY and tailor the flavors for YOU (but listen to the advice everyone offers, it's usually pretty good). Flavors are cheap (individually), so use what you need to to actually enjoy your creations.