Got my first KFL+ and R91 a couple weeks ago, and have been building 1.8Ω cotton wicked micro coils with 6 wraps of 30 gauge on a 3/32" drill bit. I've been plagued with random dry/burnt hits. Flavor would go from fabulous to less to nil, and I would get burnt hits out of the blue, powered by Provari at 3.7 to 3.9 volts. The flavor drop, after a few hits, could be solved by the occasional dry pull, and the burnt hits could be solved by a dry pull (sometimes with finger over air hole) to get more juice into the chamber.
Since this clearly seemed to be a wicking issue, I tried every possible wicking configuration: less cotton, more cotton, medium cotton, longer wicks, shorter wicks, medium wicks, wicks on the channels, off the channels, on the side. Nothing worked.
Recently my spool of 28 gauge kanthal arrived and yesterday I decided to see if it would make a difference. I've built 1.5Ω coils with 10 wraps on a 5/64" drill bit, and have not had a single. burnt or dry hit. Occasionally I will get a slight drop in flavor after a few chain hits, but it quickly recovers. This is a blessing, because the worst thing about those random burnt hits was that they'd come out of the blue- yuck. The only indicator would be that I'd hear a sort of "after-burn" sizzle after releasing the draw. FWIW, I'm using just enough fluffy cotton to easily pull through the coil without tugging. My wick ends go straight down to touch the deck and curl under a bit, without blocking the channels.
So if any of you are using 6 wraps of 30G on a 3/32" bit and plagued with burnt hits and flavor issues, you might want to try the bigger 28G coil. I don't know why (more surface area?) but this has solved the problem and I'm a happy vaper
I used to also have flavor issues after a re-fill (bottom or top) but haven't refilled yet with these new coils. I'll post back after refill if I have any problems.