(coming back up to speed on the thread)
28 vs 32... I typically run microcoils in my stuff, and a 10 wrap (~1.2 ohm) with 28 gauge is some durable stuff. That wire is (relatively) thick and holds up for a long, long time through dozens of cleanings and dry burnings.. pulling puffy, saturated wicks, you name it. The 32 was a little more finicky when it came to micros and the couple I made were a little on the fragile side; I had one pull apart when I removed the cotton (which, consequently, became my last 32g microcoil). Being thicker and lower resistance than 32, 28 takes a little longer to get going, but the bigger coil does do a great job in pumping out vapor.
But the real limiting factor is my gear. I like to vape 10-12w in my RDAs and I have a Vamo V3 and a K100 mech. I know, after spending a little bit with a MM and testing things out, that on a single battery, my Vamo tops out at about 4.5v.. it just can't boost the voltage past that. So that means that if I want to get to 12w, I really can't go much above 1.6ohms... which you really can't do with a 32g coil as you would have a really tiny, extremely hot coil that would burn as much as vaporize. And on the mech, you are looking at 8w max if you have a 32g coil (I'll spare you the numbers). Combine that with my belief that the more wraps the better.... the low resistance of the 28g makes it a perfect choice for what I have.
KFC air flow.... To me, even with the air screw removed completely, it's a tighter than I'd like. My trident clone (at the 2mm hole) and the nimbus (dual coil, with drilled out holes) are much more airy...a I've grown to prefer the airy draw. I have a single coil IGO-L that is at 1.5mm, and it'll be getting bored out in the next day or two... I just started using it again and it's a bit too tight, even at 1.5mm.
Do you "mouth hit" or "lung hit" Leo? I've found most lung hitters find the draw on the KFL to be restrictive whereas mouth hitters like me seem to find the draw to be sufficient.