Am thinking that it's a combination of proper wick density through the coil, height of build and positioning of air intake.
How are you wrapping your
coils?? Personally tension wrap all my coils, which makes duplicating and getting consistent coils much easier.
Would first play with the wick trough the coil, increasing then decreasing the amount of fiber used. What fiber are you using, by the way?? Each is slightly different, and some are a bit more finicky than others.
Feel better now that know a VTC5 is involved, but still at 0.22 ohms, one must remain diligent cause can easily stress out the 5 when going that low.
So much with building has to do with play with it till it vapes right, and recognizing why it vapes better or worse, after being played with, and learn from that.