I open my JFC 1-1/2 turns (same as my KM3). I have not tried any other setting. I started with 1-1/2 and never had any issues so that's where I have set it since. I use 70/30 (PG/VG). My coil is 28 gauge, 8-wraps, 2.5mm inside diameter. My K5 is always in an upright position.
Not sure how thick your wick is but I can tell you less is not more. More is more. Most people use thinner wicks if they think they have problems. Go thicker. Not thinner. I fan each side out (once
threaded
through the coil) and trim off about 20% of its width. With regard to length...just so it reaches the deck. No more, no less.